MathBrush

Practice

Same pattern as Footpath — circular tiles. New numbers, new story. Try each one on paper, then check the working below — or watch it drawn out, the same way the problem above is.

Question 1

The figure shows a rectangular display case and an L-shaped countertop border around it in a bakery. The width of the border is 40 cm. The border is covered with 30 circular coasters of diameter 20 cm, following the pattern shown in the figure. Each coaster touches the ones next to it. What is the area of the border not covered by the coasters? (Take π = 3.14)

An L-shaped countertop border runs along the top and right edges of a rectangular display case, covered with circular coasters that touch each other, each sitting inside its own square of the border.display case40 cm20 cmLpattern continues around the corner

Work it out on paper, then check below. ▶ See the working

The working