1. Area of one step = (PI*104^{2} - PI*40^{2}) / 12
2. MA^{2} = 104^{2} - 40^{2} (etc.)
3. The PLAN diagram will be identical with that for Q.2.
The ELEVATION shows that the vertical height of B
above A is 15 step thicknesses, i.e. 300 cm.
So AB^{2} = 300^{2} + 192^{2} (etc.)
THIS MONTH'S QUIZ
1. If AB = 16 cm, BC = 18 cm and CA = 19 cm and A, B and C are the centres of the three circles, find their radii.
2. If DE = 31 cm, EF = 36 cm, FG = 40 cm, GH = 43 cm and HD = 36 cm find the radii of the five circles.
3. If IJ = 1.8 cm, JK = 2.1 cm, KL = 2.1 cm, LM = 2.5 cm and MN = 2.8 cm, find the length of NI.