Answer:
see explanation
Step-by-step explanation:
The surface area (A) of a sphere is calculated as
A = 4πr² ← r is the radius, here r = 9, thus
A = 4π × 9² = 4π × 81 = 324π ≈ 1017.9 units²
Answer:
-7
Step-by-step explanation:
-2 + 3v = -23 >> -2 + 23 = -3v >> 21 = -3v >> v = -7
Answer:

Step-by-step explanation:
Factorise in order to reveal factors.

Answer:
5√3 / 2
Step-by-step explanation:
tan 30 = ( 5 / 2 ) / y
1 / √3 = 5 / 2y
2y = 5√3
y = 5√3 / 2