11.
(87+91+86+x)/4=90.
x=96.
13.
50×y > 130.
the lowest number could be 3, because 50×2=120, which is less than 130.
Answer:
C
Step-by-step explanation:
if not c it's B
529.2 .......................................
Since there are

in a circle, and central

, you can see that the part "sliced out" by the central angle is

of the whole circle.
This means that the length of the intercepted arc

is

of the circumference of the circle. So,