## zepdrix one year ago Studayyyyyyy Taymeeeeeee!

1. zepdrix

|dw:1432784644165:dw| @Compassionate come nao!! +_+

2. zepdrix

Circle b has area 121 times greater than area if a $\Large\rm A_b=121A_a$

3. zepdrix

Area is pi(r)^2, ya?

4. zepdrix

$\Large\rm A_b=121A_a$So I'll plug in our formula for area,$\Large\rm \pi r_b^2=121(\pi r_a^2)$They told us the radius of circle b is 44,$\Large\rm \pi (44)^2=121(\pi r_a^2)$Solve for r! :)

5. Compassionate

OS just loaded for me. Sigh. Okay, wait so we did the formula for a circle and plugged in the parts, but what is the pi(44)^2 at the end?

6. zepdrix

I hope the r's weren't too confusing. I was calling the radius of circle b, $$\Large\rm r_b$$ and the radius of circle a, $$\Large\rm r_a$$. So we have our area relationships,$\Large\rm \color{orangered}{A_b}=121\color{royalblue}{A_a}$I'm plugging in the formula for area of a circle on each side, with a's radius on the right, b's radius on the left side,$\Large\rm \color{orangered}{\pi (r_b)^2}=121\cdot\color{royalblue}{\pi(r_a)^2}$And then I'm plugging in the value of the radius of circle b, they told us the radius of circle b is 44,$\Large\rm \color{orangered}{\pi (44)^2}=121\cdot\color{royalblue}{\pi(r_a)^2}$

7. zepdrix

The pi(44)^2 is pi times radius of circle b squared, area of circle b.