Question

Need to find the number for a

Answer 1

Answer to the first triangle: 15

To solve this we will use the Pythagorean theorem

Pythagorean theorem formula: $a^{2} + b^{2} =c^{2}$

Lets do the first triangle. 

17 is the hypotenuse, so its going to replace c in the formula.

8 is the height and it is going to replace a in the formula.

a is what we are trying to find, so our b in the equation is going to be the unknown.

$8^2 + b^2 = 17^2$

$64 + b^2 = 289$

$b^2 = 289 - 64$

$b^2 = 225$

$\sqrt{b^2} = \sqrt{225}$

$b = 15$

now we know that the missing length in the first triangle (a) is 15

Can you solve the Other one?

Just comment if you need help on the other one.