Problema Solution

The volume of a pyramid is given by the formula

V = bh/3

where B is the area of its base and h is its height. The volume of the following pyramid is 88 cubic centimeters. Find the dimensions of its rectangular base if one edge of the base is 2 centimeters longer than the other and the height of the pyramid is 11 centimeters.

cm (smaller value)

cm (larger value)

Answer provided by our tutors

Volume (V) = 1/3 x Area of base (B) x Perpendicular height (H)

Consider that length of the base is (L + 2) and breadth is L

88 = 1/3 x L(L + 2) x 11

264 = 11L(L + 2)

11L(L + 2) = 264

L (L + 2) = 24

L2 + 2L = 24

L2 + 2L - 24 = 0

L2 + 6L - 4L - 24 = 0

L(L + 6) - 4(L + 6) = 0

(L + 6 ) (L - 4) = 0

then L + 6 = 0 or L - 4 = 0

then L = - 6 and L = 4

But length can not be negative. Which L > 0

4 cm is more suitable for L

Length = L + 2 = 6cm

Breadth = L = 4cm

Answered By

U S M C PERERA

An Educationist from the University of Sri Jayewardena Pura (Sri Lanka)

Search me in face book "usmcpholdings@gmail.com" or "sereneei@live.com"

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