About This Set
These 25 are harder than the first two sets. Most questions need two steps or have to be worked backwards from what is given: a cuboid from its three face diagonals, a prism's height from its volume or total surface, a cylinder from the sum of its radius and height, a cone from its total surface and slant height, a pipe's radii from its metal and its two surfaces, a frustum cut off a cone, the surface left after scooping or hollowing out a solid, and marbles that raise the water in a beaker. Items marked [Tier 2] (the regular tetrahedron, a pyramid on a triangular base and a well with an embankment) are mostly asked in Tier 2, so leave them for later if you are preparing for Tier 1 alone. Two habits help: sketch the solid and mark which surfaces are really on the outside, and check that the answer fits the data (an inner radius smaller than the outer one, a whole number of marbles, a height that is less than the slant). Allow about 40 minutes. 18 or more right means you are ready for the PYQ Practice Sets.