An triangular prism has base xcm, height (x+4)cm and length 4xcm. Find the volume of the prism in terms of x. Find the volume when x=2cm.

This question combines knowledge of volume equations with using unknown variables. We know the volume of a prism is the area of the face multiplied by the length. The first step would be to find the area of the triangular face, using the area of a triangle, 1/2 * base * height = area. 1/2 * b * h = 1/2 * (x) * (x+4) = 1/2* (x2 + 4x) = 1/2x2 + 2x cm2Next we find the volume of the prism by multiplying this expression by the length, 4x cm. length * area = 4x * (1/2x2 + 2x) = 2x3 + 8x2 cm3We now have an expression for the volume with an unknown x. Next, we can substitute x=2 into the expression. 2*(2)3+ 8*(2)2= 28 + 84 = 16 + 32 = 48cm3

MP

Related Maths GCSE answers

All answers ▸

Work out the ratio between the surface area of sphere of radius 6cm and the total surface area of a hemisphere of radius 9cm.


Solve the simultaneous equation: y=x^2+2x-2 y=4x+6


Solve the simultaneous equation: 4x-11y=34 and 2x+6y=-6


An area of a garden needs to be tiled. It consists of a square area of 10m by 10m, with an outdoor pool in the middle of radius 3m. The tiles to be used are 50cm by 50cm, and cost 50p per tile. Find out how much it will cost to tile the area.