Monday, April 5, 2010

Area P6 2009 SA1 P2 RGS Q14

14. The figure below is made up of two identical right-angled triangles, a small square and a big square. The perimeter of the shaded region is 50 cm, and the total area of the two unshaded squares is 254.5 cm. Find the total area of the two shaded right-angled triangles. [5]



Firstly, we may adjust the figure and add a red rectangle to form another square as follows:

2 L + 2 B
50 – 3 – 3 = 44

L + B
44 ÷ 2 = 22

Area of biggest square (L + B) x (L + B)
22 x 22 = 484

484 – 254.5 = 229.5

229.5 ÷ 2 = 114.75 cm2


The total area of the two shaded right-angled triangles is 114.75 cm2.

No comments:

Post a Comment