SOLUTION: 3 congruent squares of side length 16 are inscribed in a circle as shown. Find the area of the circle in terms of pi.

Algebra ->  Length-and-distance -> SOLUTION: 3 congruent squares of side length 16 are inscribed in a circle as shown. Find the area of the circle in terms of pi.       Log On


   



Question 1178914: 3 congruent squares of side length
16 are inscribed in a circle as
shown. Find the area of the
circle in terms of pi.

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!



We let h equal the little distance from the top of the bottom square to the
center of the circle.

The two red lines marked r are radii.

There are two right triangles, and their hypotenuses are the
radii, of length r.

Applying the Pythagorean theorem to the upper right triangle:

%2816-h%29%5E2%2B16%5E2=r%5E2
256-32h%2Bh%5E2%2B256=r%5E2
512-32h%2Bh%5E2=r%5E2

Applying the Pythagorean theorem to the lower right triangle:

%2816%2Bh%29%5E2%2B8%5E2=r%5E2
256%2B32h%2Bh%5E2%2B64=r%5E2
320%2B32h%2Bh%5E2=r%5E2

We set the two expressions for r2 equal:

512-32h%2Bh%5E2%22%22=%22%22320%2B32h%2Bh%5E2

Subtract h2 from both sides:

512-32h%22%22=%22%22320%2B32h

-64h%22%22=%22%22-192

h=3

We substitute h=3 in

320%2B32h%2Bh%5E2=r%5E2
320%2B32%283%29%2B%283%29%5E2=r%5E2
320%2B96%2B9=r%5E2
425=r%5E2

The area of a circle is

A=pi%2Ar%5E2

So the area of the circle is

A=425pi   <--answer

Edwin