Question 741120
Angle 1 + Angle 2 = 180 (supplementary angles = 180 degrees)
Angle 2 + Angle 3 = 90 (complementary angles = 90 degrees)

Angle 1 = 2x and Angle 2 = 8/5 x  add these two to solve for x.

2x + 8/5 x = 180 (clear the fraction by multiplying each term by 5)

10x + 8x = 900
18x = 900
x = 50

So, now that we have x, we can find Angle's 1 & 2

Angle 1 = 2x = 2(50) = 100 degrees
Angle 2 = 8/5 x = 8/5(50) = 80 degrees

Since Angle 2 + Angle 3 = 90, then
80 + Angle 3 = 90
Angle 3 = 90 - 80
Angle 3 = 10 degrees