We know that the right triangle has one 90 degree angle and two acute (< 90 degree) angles. Since the sum of the angles of a triangle is always 180 degrees.
<u>To find x:</u>
(10x - 20) + (6x + 8) = 180
16x - 12 = 180
+12 +12
16x = 192
----- -----
16 16
x = 12
<u>Check:</u>
(10(12) - 20) + (6(12) + 8) = 180
(120 - 20) + (72 + 8) = 180
100 + 80 = 180
180 = 180
<u>Angle (10x - 20):</u>
(10(12) - 20)
(120 - 20)
100
<u>Angle (6x + 8):</u>
(6(12) + 8)
(72 + 8)
80
Answer:
and 
this is what i think, hope it helps
The answer would be -15.74
