The answer is C. 90 degrees.
This is because angle R is one of the four angles of a square.
I hope this helps.
Vertex form: y = a(x - h)² + k
h = 2
k = -1
y = 0
x = 5
0 = a(5 - 2)² - 1
0 = 9a - 1
a = 1/9
Can u just post the whole question or elaborate further
The mean can be found by adding the two numbers and dividing by 2
let the second number be y
(x + y)/2 = 1/2x + 1
solve for y
multiply each side by 2
x + y = 2(1/2x + 1)
distribute
x + y = x + 2
subtract x on both sides
y = 2
ANSWER: the second number is 2