Answer:
a
Explanation:
For this question we need to use the Pythogorean Theorem as we know its a right angle and are missing a side.
The Pythogorean Theorem is
, where a and b are any side other than the hypothenuse, the longest line, and c is the hypothenue.
So, plug in the values and you get
![7^(2) + 2^(2) = x^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/2b1ld02nxk2vjalol573b7rdtmjch9kpyf.png)
![7^(2) + 2^(2) = 4 + 49 = 53](https://img.qammunity.org/2021/formulas/mathematics/high-school/drk92z8i5fn2kfbfhzk5av1so9vsh5rsgg.png)
So now we just find the square root, which as it isn't a square number we can just leave it as it is, as a surd, so the answer is 'a'.