This math topic focuses on calculating the radius of a circle given its area. Each problem presents a different area, and students must rearrange the area formula, \( A = \pi r^2 \), to solve for the radius \( r \), showing an application of algebraic manipulation and understanding circle geometry. The students are given multiple choice options for each problem. This is part of a broader introduction to circle geometry, covering concepts like circle areas and circumferences.

Work on practice problems directly here, or download the printable pdf worksheet to practice offline.

more
View

Area of a Circle - Area and Equation to Radius (Pi Value) Worksheet

Mobius Math Academy logo
Math worksheet on 'Area of a Circle - Area and Equation to Radius (Pi Value) (Level 1)'. Part of a broader unit on 'Geometry - Circle Partial Area and Circumference - Intro' Learn online: app.mobius.academy/math/units/geometry_circles_partial_perimeter_area_intro/
1
If the area of this circle is 4, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 4=Pi times r to the power of 2
a A LaTex expression showing r=square root of 4 over 2 times Pi
b A LaTex expression showing r=square root of 4 over Pi
c A LaTex expression showing r=square root of 2 times Pi over 4
d A LaTex expression showing r=4 times square root of 2 over Pi
2
If the area of this circle is 9, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 9=Pi times r to the power of 2
a A LaTex expression showing r=square root of 9 over Pi
b A LaTex expression showing r=9 times square root of 2 over Pi
c A LaTex expression showing r=square root of 9 over 2 times Pi
d A LaTex expression showing r=square root of 2 times Pi over 9
3
If the area of this circle is 8, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 8=Pi times r to the power of 2
a A LaTex expression showing r=square root of 8 over Pi
b A LaTex expression showing r=8 times square root of 2 over Pi
c A LaTex expression showing r=square root of 2 times Pi over 8
d A LaTex expression showing r=square root of 8 over 2 times Pi
4
If the area of this circle is 10, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 10=Pi times r to the power of 2
a A LaTex expression showing r=square root of 10 over Pi
b A LaTex expression showing r=square root of 10 over 2 times Pi
c A LaTex expression showing r=square root of 2 times Pi over 10
d A LaTex expression showing r=10 times square root of 2 over Pi
5
If the area of this circle is 7, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 7=Pi times r to the power of 2
a A LaTex expression showing r=square root of 7 over 2 times Pi
b A LaTex expression showing r=square root of 2 times Pi over 7
c A LaTex expression showing r=7 times square root of 2 over Pi
d A LaTex expression showing r=square root of 7 over Pi
6
If the area of this circle is 6, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 6=Pi times r to the power of 2
a A LaTex expression showing r=square root of 6 over Pi
b A LaTex expression showing r=square root of 6 over 2 times Pi
c A LaTex expression showing r=square root of 2 times Pi over 6
d A LaTex expression showing r=6 times square root of 2 over Pi
7
If the area of this circle is 5, what it its radius?
A LaTex expression showing A=Pi times r to the power of 2 \\ 5=Pi times r to the power of 2
a A LaTex expression showing r=square root of 5 over Pi
b A LaTex expression showing r=square root of 5 over 2 times Pi
c A LaTex expression showing r=5 times square root of 2 over Pi
d A LaTex expression showing r=square root of 2 times Pi over 5