Answer:
59
Explanation:
The sum of the opposite interior angles of a triangle is equal to the exterior angle
4x+11 +51 = 10x -10
Combine like terms
4x+62 = 10x -10
Subtract 4x from each side
4x+62-4x = 10x-10-4x
62 = 6x-10
Add 10 to each side
62+10 = 6x-10+10
72 = 6x
Divide by 6
72/6 = 6x/6
12 =x
We want to find angle D
<D =4x+11
= 4*12 +11
= 48+11
= 59