the areas of two circes are directly roportional to their radii squared (a/a1=r^2 / r1^2) Find the area A1 if A= 78.5, r=5 and r1=8.

Question

the areas of two circes are directly roportional to their radii squared (a/a1=r^2 / r1^2)  Find the area A1 if A= 78.5, r=5 and r1=8.

mertsj · Answer

Is that supposed to be an equal sign instead of a plus sign?

mertsj · Answer

Then just plug in the given values and solve for a1

anonymous · Answer

200.96  yupz... simply put in the values

phi · Answer

you start with
$$ \frac{A}{A_1} = \frac{r^2}{r_1^2}$$
they tell you r is 5  and $r_1 $ is 8, and A is 78.5.  Replace the letters with these numbers.
$$ \frac{78.5}{A_1} = \frac{5^2}{8^2}$$
can you find $A_1$ ?
one way is "flip" both fractions  and then multiply both sides by 78.5 and simplify
another way is "cross multiply", then divide both sides by 5^2 (which is 25)
can you finish ?

anonymous · Answer

yes,, i got it tyty!!

phi · Answer

yw