area= π/4 (10^2 - 7^2) = 51π/4
cost = 5 * area/1 = 255π/4
A golden ring is 20mm in diameter and has a 14mm hole in the middle.i). What is the area of the ring[Take π=22/7].ii.) If 1mmsquare of gold costs gh5.00,Calculate the cost of the ring.
2 answers
d = outer diameter
D = inside diameter
Area = Area of outer diameter - area of inner diameter
A = d² π / 4 - D² π / 4
A = ( d² - D² ) π / 4
A = ( 20² - 14² ) π / 4
A = ( 400 - 196 ) π / 4
A = 204 • π / 4
A = 50 π
A = 50 • 22 / 7 = 1100 / 7
A = 157.1428571428571 mm²
Gold is paid by volume, not by area.
D = inside diameter
Area = Area of outer diameter - area of inner diameter
A = d² π / 4 - D² π / 4
A = ( d² - D² ) π / 4
A = ( 20² - 14² ) π / 4
A = ( 400 - 196 ) π / 4
A = 204 • π / 4
A = 50 π
A = 50 • 22 / 7 = 1100 / 7
A = 157.1428571428571 mm²
Gold is paid by volume, not by area.
2 answers