How would I solve Part B?

D (-4, -9)

Step-by-step explanation:

midpoint formula:

(x₁ + x₂) / 2 , (y₁ + y₂) / 2

plug in C (2,7)

(2 + x₂) / 2 , (7 + y₂ ) / 2 = (-1, -1)

(2 + x₂) / 2 = -1

multiply each side by 2

2 + x₂ = -2

subtract 2 from both sides

x₂ = -4

(7 + y₂) / 2 = -1

multiply each side by 2

7 + y₂ = -2

subtract 7 from both sides

y₂ = -9

D (-4, -9)

i'm pretty sure it's 477,585,296, but perhaps my math is incorrect.

50.6

step-by-step explanation: