Answer:
A. x=5
Explanation:
This triangle is a right triangle. We know this because of the little square in the corner that represents a right angle. Therefore, we can use Pythagorean Theorem.

where a and b are the legs and c is the hypotenuse.
We know that 4 and 3 are the legs, because they form the right angle. We also know that x is the hypotenuse, because it is opposite the right angle.
a=4
b=3
c=x
Substitute these values into the formula.

Evaluate the exponents.
4^2 is the same as 4*4, which is 16.
3^2 is the same as 3*3, which is 9.

Add 16 and 9.

We are trying to find x, which means we have to get x alone. x is currently being squared. To undo this, take the square root of both sides. The exponent and square root will cancel, leaving x by itself.



Therefore the correct answer is A: x=5