Can someone please help me, I really don't understand it. I'll brainliest you if you want. I just really need to know how to get the answer.

the answer for no.19. is 129°

Step-by-step explanation:

firstly as you can see line DE is actually the diameter which is equal to 180°. the angle CD is equal to 51° so all we have to do is minus 51° from 180° which is equal to 129°.

You can also minus 108° from 180° the answer is 72° therefore the angle for line BFE is 72°. Add all the answer should be 360° which is the total degrees for a circle.

D. No, a and b are interchangable, and c is the longest side.

Step-by-step explanation:

Given that Summer looked at the formula for the Pythagorean Theorem,

, she said that it didn’t matter which sides of a right triangle were a, b, and c

She is wrong because c should be the hypotenuse in this case. Hypotenuse being the largest side of a right triangle has the square as the sum of squares of other legs.

But a and b the legs can be interchanged here, but a, c or a, b cannot be interchanged.

Hence we have out of 4 options only one option is right

Option D . No, a and b are interchangable, and c is the longest side.