Theory question 302
Statistical Maps and DiagramsThe Table G below shows the value of commodities exported by a country in the year 2020. Study and use it to answer the questions that follow.
Table G
Cocoa: 729 US dollars
Diamond: 400
Gold: 900
Crude oil: 196
(a) Using a radius scale of 1 cm to represent 10 units, draw proportional circles to represent the value of exported commodities by the country in the year 2020. [Use the square root method] (b) Calculate the percentage of the value of gold exported in the year 2020.
Show the model answer
(a) Square roots: cocoa √729 = 27 → radius 2.7 cm; diamond √400 = 20 → 2.0 cm; gold √900 = 30 → 3.0 cm; crude oil √196 = 14 → 1.4 cm. Draw four circles with these radii, label each with the commodity and value, and add a title and the scale.
(b) Total = 729 + 400 + 900 + 196 = 2,225; gold = 900 ÷ 2,225 × 100 ≈ 40.4%.
Take square roots before scaling.