2006-10-10 17:38:28 · 5 answers · asked by al-leff a 1 in Science & Mathematics ➔ Mathematics
That's just the area of one circle (pi x r^2) subtracted from another. In this case:
pi x (7.875/2)^2 - pi x (4.5/2)^2 = 32.8 in^2
Hope that helps!
2006-10-10 17:46:34 · answer #1 · answered by Doctor Why 7 · 0⤊ 0⤋
The area of the 7 7/8 in. circle minus the area of the 4 1/2 in. circle.
2006-10-11 00:52:30 · answer #2 · answered by MailorderMaven 6 · 0⤊ 0⤋
Use the formula for the area between two concentric circles:
pi*R^2 - pi*r^2,
where R is the outer radius and r is the inner radius, so just halve the diameters you're given and plug in them into this.
2006-10-11 00:45:45 · answer #3 · answered by James L 5 · 0⤊ 0⤋
OD: pi*r&2=pi*3.9375^2=15.504*pi=48.707 in^2
ID: pi*r^2=pi*2.25^2=5.0625*pi=15.904
x sec of metal=OD area-ID area=48.707-15.904=32.803 in^2
2006-10-14 21:50:38 · answer #4 · answered by yupchagee 7 · 0⤊ 0⤋
Approximately 32.8 square inches...
2006-10-11 00:48:31 · answer #5 · answered by rocketman33 2 · 0⤊ 0⤋