The figure appears to be a triangle with the following measures:
Opposite Side = a = 6
Adjacent Side = b = 15
Hypotenuse = c = unknown
To be able to find the measure of the unknown side, since it appears to be a right triangle, we will be using the Pythagorean Formula:

![\text{ c = }\sqrt[]{a^2+b^2}](https://img.qammunity.org/2023/formulas/mathematics/college/snwjlnky39t9kxlnrd249m0l3gizvkff3i.png)
![\begin{gathered} \text{ c = }\sqrt[]{(6)^2_{}+(15)^2} \\ \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/clrdzyt5yyrubc35fk31r2umfiyy4q1js8.png)
![\text{ = }\sqrt[]{36\text{ + 225}}](https://img.qammunity.org/2023/formulas/mathematics/high-school/klqvo5iu9esy5li9i6prsvnqfdgc9thyxo.png)
![\text{ = }\sqrt[]{261}](https://img.qammunity.org/2023/formulas/mathematics/high-school/dsbin44vez0anenvxyyla5gff47gmk4sab.png)
![\text{ c = }\sqrt[]{261}\text{ = 16.1554944214}](https://img.qammunity.org/2023/formulas/mathematics/high-school/xakmfugxyszjdjm029a4iou0kcss4yvob1.png)