this circle has a circumfrence of 60 centimeters. the measure of

Question

this circle has a circumfrence of 60 centimeters. the measure of <abc is 72 degrees. what is the the length of ac?
12 centimeters
20 centimeters
24 centimeters
36 centimeters

ying has an exercise ball that is 20 inches in diameter. which of the following represents the surface area of the exercise ball?
133pi square inches
400pi square inches
1,333pi square inches
1,600pi square inches

anonymous · Answer

attachment

anonymous · Answer

circ.=2*pi*r =60(given)

arc is fraction circ. =72/360=   1/5

so 1/5 *2*pi*r  =1/5 (60)=12

anonymous · Answer

what about the second question?

anonymous · Answer

surface area of sphere    4*pi*r^2
r=20/2=10 
r^2=10*10=100
put it in  4*pi*100=400pi
make sure you understand  or let me know

anonymous · Answer

quadrilateral GHIJ has congruent diagonals that bisect one another. What kind of quadrilateral must GHIJ be?
rectangle
non-rectangle parallelogram
non-parallelogram kite
trapezoid

anonymous · Answer

don't know that sorry

anonymous · Answer

a square has equal diagonals that bisect

anonymous · Answer

I suppose that a square is a rectangle I'll go for that