the side length of the square a hollow shaft has a cross-sectional area of 720mm², if its internal diameter is 4.5mm, calculate its outside radius 6. The area of a trapezium is 8mm², the shorter side of the two parallel sides is 2mm less than the length of the longer side while its perpendicular height is 1mm less than the length of the shorter side, find; a) the length of the shorter parallel side b) the length of the longer parallel side c) the length of the perpendicular height