Answer: OPTION B.
Step-by-step explanation:
Given the endpoints of the diameter of the circle, we need to find the midpoint, which is the center of the circle.
The following formula is used to calculate the Midpoint:

Given the endpoints of the diameter of the circle:

We can identify that:

Then, we can substitute these values into the formula:

Therefore, the center of the circle is: 
Answer: a = -5
Step-by-step explanation:
First, open up the brackets, and solve it
-12a -42 = -22 -8a. (-6 x 2a, and -6 x 7)
bring the -8a to the left side, so that all the a’s are together
-12a -42 + 8a = -22 (add -42 on both sides like we did with -8a)
-12a + 8a = -22 + 42
solve
-4a = 20
divide -4 on both sides
a = -5
Answer:
d = 157.5 m
Step-by-step explanation:
from similar triangle:
350/400 = d/180
d = 350/400 * 180
d= 157.5 m