Fonte: https://crowdin.com/project/mathtools/pt-BR#

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ strings.xml
  ~ Copyright (C) 2014 Amin Bandali <me@aminb.org>
  ~
  ~ MATHTools is free software: you can redistribute it and/or modify it
  ~ under the terms of the GNU General Public License as published by the
  ~ Free Software Foundation, either version 3 of the License, or
  ~ (at your option) any later version.
  ~
  ~ MATHTools is distributed in the hope that it will be useful, but
  ~ WITHOUT ANY WARRANTY; without even the implied warranty of
  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  ~ See the GNU General Public License for more details.
  ~
  ~ You should have received a copy of the GNU General Public License along
  ~ with this program. If not, see <http://www.gnu.org/licenses/>.
  -->

<resources>

    <!-- Menu -->
    <string name="action_settings">Configurações</string>
    <string name="action_feedback">Comentários</string>
    <string name="action_about">Sobre</string>
    <string name="action_cheat_sheet">Folha de dicas</string>
    <string name="action_help">Ajuda</string>

    <!-- General -->
    <string name="app_name">MATHTools</string>
    <string name="cheat_sheet">Folha de dicas</string>
    <string name="coming_soon">Em breve</string>
    <string name="coming_soon_sections_desc">Seções cinza serão adicionadas gradualmente em lançamentos futuros.</string>
    <string name="got_it">Entendi</string>
    <string name="changelog">Registro de Alterações</string>

    <!-- Main Fragment Navigation -->
    <string name="vectors">Vetores</string>
    <string name="geometry">Geometria</string>
    <string name="trigonometry">Trigonometria</string>
    <string name="calculus">Cálculo</string>

    <!-- Font Awesome icon strings (DO NOT TRANSLATE) -->
    <string name="fa_vectors">{fa-arrow-up}</string>
    <string name="fa_geometry">{fa-cube}</string>
    <string name="fa_trigonometry">{fa-circle-thin}</string>
    <string name="fa_calculus">{fa-book}</string>

    <!-- Feedback Fragment -->
    <string name="get_in_touch">Entre em contato!</string>
    <string name="feedback_desc">Se você viu um problema, há uma funcionalidade específica que está faltando e você acha que se encaixaria bem no aplicativo ou você simplesmente tem uma sugestão, sinta-se livre para enviar-me um email ou deixar uma análise/comentário na página do aplicativo no Google Play!</string>
    <string name="google_play">Google Play</string>
    <string name="leave_a_review">Deixe uma análise/comentário</string>
    <string name="email">Email</string>
    <string name="my_email">me\@aminb.org</string>
    <string name="twitter">Twitter</string>
    <string name="my_twitter">\@aminban</string>
    <string name="google_plus">Google+</string>
    <string name="my_google_plus">+AminBandali</string>
    <string name="email_subject">Comentários sobre o MATHTools</string>
    <string name="email_body">Oi Amin, Eu estou usando o MATHTools v%1$s e aqui está meu comentário:\n\n</string>
    <string name="shoot_me_an_email">Envie-me um e-mail!</string>
    <string name="no_email_apps_installed">Não há aplicativos de e-mail instalados.</string>

    <!-- About Dialog -->
    <string name="title_about"><![CDATA[
        <b><i><font color="#FFFFFF">MATHTools</font></i></b>&nbsp;<small><font color="#EEEEEE">v%1$s</font></small>
    ]]></string>
    <string name="about_ok">OK</string>
    <string name="about_body"><![CDATA[
        <b><i>MATHTools</i> App</b><br>
        Author: <a href="http://aminb.org">Amin Bandali</a><br>
        Get: <a href="https://github.com/aminb/mathtools">Código-fonte no GitHub</a><br>
        <br><br>
        Agradecimentos especiais ao <i>incrível</i> <b>Michael Cook</b><br>
        pelo belo logotipo do aplicativo!<br>
        <b><a href="https://www.google.com/+michaelcook">+MichaelCook</a></b><br>
        <b><a href="https://plus.google.com/102718493746376292361">+Cookicons</a></b><br><br>
        <b>Obrigado a estes projetos de código aberto:</b><br>
        <b><a href="https://github.com/gabrielemariotti/cardslib">Card Library</a></b> and
        <b><a href="https://github.com/gabrielemariotti/changeloglib">ChangeLog Library</a></b><br>
        <i>by Gabriele Mariotti</i><br><br>
        <b><a href="https://github.com/JoanZapata/android-iconify/">Android Iconify</a></b><br>
        <i>by Joan Zapata</i><br><br>
        <b><a href="http://commons.apache.org/math/">Apache Commons Math</a></b><br>
        <i>by The Apache Software Foundation</i><br><br>

    ]]></string>


    <!-- Help Dialog -->
    <string name="title_help"><![CDATA[
        <b><i><font color="#FFFFFF">MATHTools</font></i></b>&nbsp;<small><font color="#EEEEEE">%1$s</font></small>
    ]]></string>

    <!-- Lines Help -->
    <string name="lines_help_body"><![CDATA[
        <b><i>Analisador de Reta</i></b><br><br>

        - <i>Vetor</i> equação de uma reta:<br>
        <b>R<sup><small>2</small></sup>:</b>
        (x, y) = (<b>x<sub><small>0</small></sub></b>, <b>y<sub><small>0</small></sub></b>) + k (<b>d<sub><small>x</small></sub></b>, <b>d<sub><small>y</small></sub></b>)<br>
        <b>R<sup><small>3</small></sup>:</b>
        (x, y, z) = (<b>x<sub><small>0</small></sub></b>, <b>y<sub><small>0</small></sub></b>, <b>z<sub><small>0</small></sub></b>) + k (<b>d<sub><small>x</small></sub></b>, <b>d<sub><small>y</small></sub></b>, <b>d<sub><small>y</small></sub></b>)<br>

        (<b>x<sub><small>0</small></sub></b>, <b>y<sub><small>0</small></sub></b>) - ou (<b>x<sub><small>0</small></sub></b>, <b>y<sub><small>0</small></sub></b>, <b>z<sub><small>0</small></sub></b>) - é um ponto na reta.<br>
        (<b>d<sub><small>x</small></sub></b>, <b>d<sub><small>y</small></sub></b>) - ou (<b>d<sub><small>x</small></sub></b>, <b>d<sub><small>y</small></sub></b>, <b>d<sub><small>y</small></sub></b>) - é o vetor diretor da reta.<br><br>

        - <i>Padrão</i> equação de uma reta:<br>
        <b>R<sup><small>2</small></sup>:</b>
        <b>A</b>x + <b>B</b>y + <b>C</b> = 0<br>
        <b>R<sup><small>3</small></sup>:</b>
        -<br>
        <b>A</b> e <b>B</b> (coeficientes de x e y) são os componentes x e y do vetor normal respectivamente.

    ]]></string>

    <!-- Vectors section titles -->
    <string name="vectors_products">Produtos</string>
    <string name="vectors_projections">Projeções</string>
    <string name="vectors_lines">Retas</string>
    <string name="vectors_planes">Planos</string>

    <!-- Strings Common in "Vectors" sections -->
    <string name="vector_space">Espaço vetorial:</string>
    <string name="two_d_space">Espaço 2D</string>
    <string name="three_d_space">Espaço 3D</string>
    <string name="r2">R&lt;sup&gt;&lt;small&gt;2&lt;/small&gt;&lt;/sup&gt;</string>
    <string name="r3">R&lt;sup&gt;&lt;small&gt;3&lt;/small&gt;&lt;/sup&gt;</string>
    <string name="ax">a&lt;sub&gt;&lt;small&gt;x&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="ay">a&lt;sub&gt;&lt;small&gt;y&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="az">a&lt;sub&gt;&lt;small&gt;z&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="bx">b&lt;sub&gt;&lt;small&gt;x&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="by">b&lt;sub&gt;&lt;small&gt;y&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="bz">b&lt;sub&gt;&lt;small&gt;z&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="clear">Limpar</string>

    <!-- Products Fragment -->
    <string name="vector_multiplication">Multiplicação de vetores</string>
    <string name="a_dot_b">a . b = </string>
    <string name="a_cross_b" formatted="false">\n\na x b = (%s, %s, %s)</string>

    <!-- Projections Fragment -->
    <string name="vector_projection">Projeção do vetor</string>
    <string name="a_on_b_scalar">a para b (scalar):\n</string>
    <string name="a_on_b_vector" formatted="false">\n\na para b (vetor):\n(%s, %s</string>

    <!-- Lines Fragment -->
    <string name="line_analyzer">Analisador de retas</string>
    <string name="first_line">Primeira reta</string>
    <string name="second_line">Segunda reta</string>
    <string name="x0">x&lt;sub&gt;&lt;small&gt;0&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="y0">y&lt;sub&gt;&lt;small&gt;0&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="z0">z&lt;sub&gt;&lt;small&gt;0&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="dx">d&lt;sub&gt;&lt;small&gt;x&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="dy">d&lt;sub&gt;&lt;small&gt;y&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="dz">d&lt;sub&gt;&lt;small&gt;z&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="xp0">x&#x2032;&lt;sub&gt;&lt;small&gt;0&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="yp0">y&#x2032;&lt;sub&gt;&lt;small&gt;0&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="zp0">z&#x2032;&lt;sub&gt;&lt;small&gt;0&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="dpx">d&#x2032;&lt;sub&gt;&lt;small&gt;x&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="dpy">d&#x2032;&lt;sub&gt;&lt;small&gt;y&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="dpz">d&#x2032;&lt;sub&gt;&lt;small&gt;z&lt;/small&gt;&lt;/sub&gt;</string>
    <string name="equation_form">Forma da equação:</string>
    <string name="vector">Vetor</string>
    <string name="parametric">Paramétrica</string>
    <string name="symmetric">Simétrica</string>
    <string name="standard">Padrão</string>
    <string-array name="equation_forms_array">
        <item>@string/vector</item>
        <!--<item>@string/parametric</item>-->
        <!--<item>@string/symmetric</item>-->
        <item>@string/standard</item>
    </string-array>
    <string name="lines_intersecting">As duas retas se interseccionam.\n\nPonto de intersecção:\n(</string>
    <string name="lines_parallel">As duas retas são paralelas.\n\nDistância entre elas: </string>
    <string name="lines_identical">As duas retas são idênticas.</string>
    <string name="lines_skew">As duas retas são concorrentes.\n\nDistância entre elas: </string>
    <string name="lines_intersecting_r3">As duas retas não são paralelas e não são concorrentes.\n\nElas se interseccionam em\n(</string>
    <string name="units"> unidades</string>
    <string name="precision_pattern">###.######</string>

    <!-- Trigonometry section titles -->
    <string name="trig_calculator">Calculadora</string>

    <!-- Calculator Fragment -->
    <string name="trigonometry_calculator">Calculadora Trigonométrica</string>

</resources>