The sum of the opposite interior angles is equal to the exterior angle.
So,
∠CAB + ∠ACB = ∠CBD
x + 40 + 3x + 10 = 6x
4x + 50 = 6x
2x = 50
x = 25°
∠CAB = x + 40 = 25 + 40 = 65°
Hence, the answer is D.
The answer is false.
For a square pyramid, the volume is calculated by 1/3*B*h. The height should touch the tip and lie perpendicular to the base. Slant height is used for surface area, not volume.
