This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Thursday, August 07, 2008

Maha Bodhi Sch 2007 PSLE Math Prelim Q46



Each corner of the floor mat shown above is made up of a quadrant of radius 4 cm. Find the perimeter of the floor mat.

Solution
4 quadrants make 1 full circle
Perimeter of arcs of 4 quadrants above -----
2 x 3.14 x 4 cm = 25.12 square cm

Consider length of mat -----
40 cm – 4 cm – 4 cm = 32 cm

Consider breadth of mat -----
30 cm – 4 cm – 4 cm = 22 cm

Perimeter of mat -----
(25.12 + 32 cm + 32 cm + 22 cm + 22 cm)
= 133.12 cm (Answer)

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