Answer:
616 square centimeters
Step-by-step explanation:
Area of a circle is equal to pi × r^2. In this case, they have asked that you substitute 3.14 or 22/7 for pi, so I will be using 22/7, instead.
Diameter is equal to 2r; to find the radius, simply divide 28 by two. This gives us a radius of 14.
Multiply 14 squared by 22/7:
(22/7)(14^2)
This gives us (22/7)(196); (4312/7); 616.
Therefore, the area of the circle is approximately 616 square centimeters.
Step-by-step explanation:
1st one
2nd
4th
Equation (1)

Equation (2)

Get y alone in equation (1)

Insert y in equation (2)

Answer:
9pi
Step-by-step explanation:
circumference= 2 (pi) (r)
radius = diameter \ 2
r = 9 \ 2 = 4.5in.
c = 2 (pi) (4.5)
c = 9pi or 28.3in.
Hope this helps!