The diagram shows a model of a pyramid mounted on a base in the shape of a cuboid.
The length and width of the cuboid are both 25cm and its height is 4cm. Each of the
four faces of the pyramid is an equilateral triangle with side length 18cm. The model is
to be painted all over, except for the underside of the base, which will not be visible.
Fill in the gaps, giving your answers to three significant
figures where appropriate.
(a) The visible surface area of the cuboid is
(b) The visible surface area of the pyramid is
(c) The total surface area to be painted is
cm².
cm².
cm².
18
25