Answer:
x = 30
Step-by-step explanation:
well the two agnles are congruent so they have to equal the same angle
x+ 90 = 4x
solve for x bye subtracting x from 90
90 = 3x slove by dividing 90 by 3 getting x alone
90/3 = x
The vertex angle bisector divides the triangle into two congruent right triangles. The sine of half of the vertex angle will be half of the base divided by the side (from the definition of the sine of an angle). Then the total vertex angle is ...
α = 2×arcsin(3.5/5) ≈ 88.9°
_____
Using the Law of Cosines, the vertex angle can be found as
arccos((7^2 -5^2 -5^2)/(-2*5*5)) = arccos(1/50) ≈ 88.9°
so the ODE is indeed exact and there is a solution of the form 
. We have
With 
, we have
so
With two equal sides it’s called isosceles triangle
