Answer:
x=55°
Step-by-step explanation:
x=90-35
x=55°
(because its x+35=90°)
B
the volume (V) of a sphere =
πr³
We require to know the radius r to calculate the volume
using surface area of a sphere = 4πr² = 615.752
divide both sides by 4π
r² =
= 49.0248...
take the square root of both sides
r =
≈ 7, hence
V=
× π × 7³ = 1436.76 m³ → B

the equation is a quadratic one, and it has a positive coefficient on the leading term, meaning, is opening upwards, so it has a "burrow" for the vertex.
the minimum or lowest point for a quadratic opening upwards is, well, the vertex point :), the "x" value is the year, the "y" or f(x) value is the population, we're asked for the year, or the x-coordinate of the vertex
well