An octagon has 8 sides, a rotation of 45° (360°/8) will map the octagon onto its preimage. Answer is 8.
The moment of inertia of a spherical shell is I = mr²
If two spheres have the same moment of inertia, then
I₁ = I₂
m₁(r₁)² = m₂(r₂)²
Solve for the second mass:
m₂ = m₁ (r₁/r₂)²
Given m₁ = 1 kg, r₁ = 2 m, r₂ = 1m,
m₂ = (1 kg) (2 m / 1 m)² = 4 kg
-11.8 + 33.4y
First turn y into 1
-11.8 + 33.4 (1)
Multiply 1 by 33.4
-11.8 + 33.4
Then add
21.6
Hope this helps!!