Find the area and the circumference of a circle with radius 5yd?

2 Answers
Apr 14, 2018

C: #10pi# yards
A: #25pi# yards squared

Explanation:

Circumference: #2pir# or #dpi# (where #r# is the radius and #d# is the diameter, which is twice the length of the radius)

Area: #pir^2#

Circumference: #2*pi*5=10pi# yards (if you're using an approximation like #3.14# for #pi#, multiply that by #10#)

Area: #5^2pi=25pi# yards squared (if you're using an approximation like #3.14# for #pi#, multiply that by #25#)

Apr 14, 2018

The circumference is #31.4# #"yd"#, and the area is #78.5# #"yd"^2#

Explanation:

There are special formulas to find the circumference and area of a circle.

Circumference:
#C= 2pir#

Area:
#A = pir^2#

  • #r# is the #"radius"#
  • #pi# is approximately #3.14#

https://ncalculators.com/area-volume/circle-calculator.htm

They've given you the radius of the circle, so all you have to do is plug it into the equation:

Circumference:
#C = 2 pi r#

#C = 2(3.14)(5)#

#C = 31.4# #"yd"#.

Area:
#A = pir^2#

#A = (3.14)(5^2)#

#A = 3.14(25)#

#A = 78.5# #"yd"^2#

So the circumference is #31.4# #"yd"#, and the area is #78.5# #"yd"^2#.