Mishnayos Kesuvos Perek 6 Mishnah 6

With regard to a minor orphan girl whose mother or brothers married her off, even with her consent to a small dowry, she retains her rights to a proper dowry. And thus, if they wrote for her a dowry of one hundred or of fifty dinars, she may, upon reaching majority, exact from her mother, or brothers, or their respective estates the sum of money that is fit to be given to her as a dowry, which is one-tenth of the family’s estate. Even if she agreed to forgo part of this sum as a minor, she may collect it as an adult. Rabbi Yehuda says: If the father married off the first daughter before he died, a dowry should be given to the second daughter in the same manner that he gave one to the first daughter. And the Rabbis say: There is no ready standard, since sometimes a person is poor and then becomes wealthy, or a person is wealthy and then becomes poor, so a family’s allowance for dowries is subject to change. Rather, the court appraises the property and gives her the appropriate sum.

יְתוֹמָה שֶׁהִשִּׂיאַתָּה אִמָּהּ אוֹ אַחֶיהָ מִדַּעְתָּהּ, וְכָתְבוּ לָהּ בְּמֵאָה אוֹ בַחֲמִשִּׁים זוּז, יְכוֹלָה הִיא מִשֶּׁתַּגְדִּיל לְהוֹצִיא מִיָּדָן מַה שֶּׁרָאוּי לְהִנָּתֵן לָהּ. רַבִּי יְהוּדָה אוֹמֵר, אִם הִשִּׂיא אֶת הַבַּת הָרִאשׁוֹנָה, יִנָּתֵן לַשְּׁנִיָּה כְדֶרֶךְ שֶׁנָּתַן לָרִאשׁוֹנָה. וַחֲכָמִים אוֹמְרִים, פְּעָמִים שֶׁאָדָם עָנִי וְהֶעֱשִׁיר אוֹ עָשִׁיר וְהֶעֱנִי, אֶלָּא שָׁמִין אֶת הַנְּכָסִים וְנוֹתְנִין לָהּ: