標題:
Maths(F.3)
發問:
The ratio of the curved surface areas of two similar cones is 9:49.Find the ratio of their a)base radii b)heights c)volumes d)base circumferences Thank you!
最佳解答:
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Q3 Because of the formula of the curved surface area is (pi)r^2(degree)/360 Q3a Let the larger cone raduis be r , smaller be s (pi)r^2(degree)/360 : (pi)s^2(degree)/360 = 49 : 9 r:s = 7:3 Q3b It's indepentant on height the ratio is 1:1 Q3c Because of the formula of the volume of cones is (pi)r^3/3 using 3a the volume ratio is (pi)r^3/3:(pi)s^3/3 =(pi)r^3/3:(pi)(3r/7)^3/3 =7^3:3^3 =343:27 Q3d Because of the formula of the circumferences is 2(pi)r it is same ratio to 3a =7:3
其他解答:
Area(s) = 9:49 (a) 3:7 (b) 3:7 (c) 3:7 (d) 3:7
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