A four sided pyramid, with a vertical height of 10cm and the base 4cmx4cm is placed on the top of a cylinder with radius 1.5cm and a height of 15cm. What is the exposed surface area?
Bottom end of cylinder = 1.52x pi = 7.07cm2Cylinder shaft surface area = 3 x pi x 15 = 141.4cm2Top end of cylinder exposed = 0 Base of pyramid exposed = (4 x 4) - 7.07 = 8.9cm2Sides of pyramid = (use pythagoras) sqrt(102+22) = 10.2cm up the face of one sideUse A=1/2 x b x h = 0.5 x 4 x 10.2 = 20.4cm2 for each side so 4 x 20.4 = 81.6 cm2Total exposed surface area = 7.07 + 141.4 + 8.9 + 81.6 = 239.0 cm2
GW
Related Maths GCSE answers
All answers ▸A fair sided spinner has five equal sections numbered 1 to 5, a fair six sided dice has five red faces and one green face. what is the probability of getting an even number and the colour green
There are 5 red balls and 7 green balls in a bag. A ball is taken from the bag at random and not replaced. Then a second ball is taken from the bag. What is the probability that the 2 balls are the same colour?
Solve the equation x^2-10x+21=0
The equation of line A is y = 6x -4. The equation of line B is 2y - 12x + 14 = 0. Are these two lines parallel?