Answer:
x = 6
Step-by-step explanation:
According to Exterior Angle Property of a triangle , measure of an exterior angle is the sum of its opposite interior angles.
Using the exterior angle property ,





This answer is 15:) hope this helps
The last one (-1,0) (2, 15) (20)
Answer:
surface area of the triangular pyramid
=(1/2×9×7.8)+(3×1/2×9×12.3)
=35.1+166.05
=201.15 inch²