Answer:
16
Step-by-step explanation:
There are 2 different ways to solve this
1) The bigger triangle is 4 times bigger than the smaller one
5 x 4 = 20
3 x 4 = 12
From this method you can see they all connect so you take the smaller triangles value of 4 and multiply it by 4
4 x 4 = 16
2) Pythagorean theorem and reorganizing the formula so that the a value is found
[tex]a = \sqrt{c^{2} -b^{2} }[/tex]
