It is the math question

Please help

Asphere has a diameter of 10 in. what is the volume of the sphere?

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9