You are asked to find
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The sin of an angle equals the opposite side divided by the hypotenuse, so the next drawing will help to find the answer:
![\sin (\theta)=\frac{7}{\sqrt[]{6^2+7^2}}=\frac{7}{\sqrt[\square]{85}}](https://img.qammunity.org/2023/formulas/mathematics/college/kgprgyimvmcphe0ja8u61rq90esadmk7ea.png)
The hypotenuse is the square root of 6 to the square plus 7 to the square because of the Pythagorean theorem. In order to have a rational denominator:
![\frac{7}{\sqrt[]{85}}=\frac{7\cdot\sqrt[\square]{85}}{85}=\frac{7\cdot\sqrt[]{17}\cdot\sqrt[\square]{5}}{17\cdot5}](https://img.qammunity.org/2023/formulas/mathematics/college/6yr67ff0kwc08bt9jcdd1bdcee5gspb8bt.png)
Because