15 points+brainliest

Step-by-step explanation:

Base of the isosceles triangle = 4

Perpendicular of the triangle = 3

In an isosceles triangle , a perpendicular bisects a base equally. So, here the isosceles triangle consist of 2 right angled triangles.

In that right angled triangles,

Base = 4/2 = 2 (∵ A perpendicular divides a base into 2 equal parts. )

Perpendicular = 3

Hypotenuse = x

So , according to Pythagorean Theorem ,

Using all the values above into the formula gives :-

you answer is a

step-by-step explanation: