Question

the radius of a circle is greater than the radius of other circle by 3metre . The sum of their areas is 89 pai square metre . find the radius of each circle

Answer 1

Let the radius of one circle be R1 and II circle be R2.

R2 -R1 = 3 m.

Area of I circle=$\pi R1^2$

Area of II circle = $\pi R2^2 </p> <p>Sum of areas of two circles = = [tex]\pi (R1+3)^2+\pi R1^2= \pi (2R1^2 +6R1+9)</p><p>=89\pi$[/tex]

Cqncel π

$(R1+3)^2+\pi R1^2= (2R1^2 +6R1+9)</p><p>=89$[/tex]

Simplify to get

Cqncel π

$=  (2R1^2 +6R1-80)=0$[/tex]

$R1^2+3R1-40=0</p><p>R1=-8, 5$

R1=5 cm.

R2 =8 cm.