I need help with this problem due tonight 10 points!!!

In the image, point a marks the center of the circle. which two lengths must form a ratio of 1 : 2? (options are in the images since thought they were harmful phrases)

If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80

Akitchen is 12 ft. by 14 ft. with 10 ft. high walls. how much would it cost to put vinyl flooring in this room? $8.80 per ft