The answer is 14. The two lower angles are 50 each 100 total and so the top angle must equal 80. If you set it equal to 80 you get 14.
Answer: 73 inches high
Step-by-step explanation: 57+16=73
I have no idea I am only in Middle School
Recall that

There are three cases to consider:
(1) When

, we have

and

, so

(2) When

and

, we get

and

, so

(3) When

, we have

and

, so

So
Answer:
y = (x - 4)² - 25
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
To obtain this form use the method of completing the square.
Given
y = (x + 1)(x - 9) ← expand factors using FOIL, thus
y = x² - 8x - 9
To complete the square
add/subtract ( half the coefficient of the x- term )² to x² - 8x
y = x² + 2(- 4)x + 16 - 16 - 9
= (x - 4)² - 25 ← in vertex form