A water tank in the form of an inverted frustum of a right cone has an altitude of 38 ft., and a slant height of 46 ft. The ratio of the upper and lower radii is 5:4. Compute for the measurement of the shorter radius.
+129852 Let the radius of the lower base = R
Using the Pythagorean Theorem.....the length of the radius of the upper base =
R + √ [46^2 - 38^2] = R + √672
So
R + √672 5
_______ = ____ cross-multiply
R 4
4 [ R + √672 ] = 5R
4R + 4√672 = 5R
4√672 = R
4 (4√42) = R
16√42 = R = length of shorter radius (in feet)
+1490 A water tank in the form of an inverted frustum of a right cone has an altitude of 38 ft., and a slant height of 46 ft. The ratio of the upper and lower radii is 5:4. Compute for the measurement of the shorter radius.
Height => h = 38 ft
Slant height => H = 46 ft
Upper radius R = ? R = D * 5
Lower radius r = ? r = D * 4 
Ratio R : r = 5 : 4
Let the defference of R - r be D
D = sqrt(H2 - h2) = sqrt (672)
