Answer:
x = 45 degrees
Step-by-step explanation:
from the picture, we can see that the triangle is:
1) a right triangle (i.e one of the angles is 90 degrees)
and
2) An isosceles triangle (i.e two side lengths are equal)
Recall that for an isosceles triangle, the base angles (i.e the angles that are not 90 degrees) are identical.
In our case, we are given one of the base angles as x. By the above reasoning, the other missing base angle must also be x. Hence the three internal angles of the given triangle are 90 deg, x deg and x deg.
Also recall that the sum of the internal angles of a triangle must add up to 180 deg, hence,
90 + x + x = 180 deg (solve for x)
90 + 2x = 180
2x = 180 - 90
2x = 90
x = 90 / 2
x = 45 deg
