Answer: The last option.
Step-by-step explanation:
The triangle shown in the figure attached is a right triangle.
1. You can calculate the lenght <em>a </em>as following:


Substitute values and solve for <em>a</em>. Then, you obtain:

2. You can calculate the lenght<em> b </em>as following:


Substitute values and solve for <em>b</em>. Then, you obtain:

