PSLEThe figure is made up of two rectangles, JKRP and PQMN, and two right-angled isosceles triangles, KLR and MLQ. KJ = 7 cm, MN = 4 cm and KR =
s cm. JPN and LRQP are straight lines.
- Find the length of JN in terms of s. Give your answer in the simplest form.
- Find the total area of the figure when s = 10.
(a)
Length RQ
= 7 - 4
= 3 cm
Length LR =
s cm (Isosceles triangle)
Length QM
= Length CG
= (
s + 3) cm (Isosceles triangle)
Length JN
=
s +
s + 3
= (2
s + 3) cm
(b)
Area of Rectangle JKPR
= 10 x 7
= 70 cm
2 Length PN
=
s + 3
= 10 + 3
= 13 cm
Area of Rectangle MNPQ
= 13 x 4
= 52 cm
2 Area of Triangle KLR
=
12 x 10 x 10
= 50 cm
2 Area of Triangle LMQ
=
12 x 13 x 13
= 84.5 cm
2 Total area of the figure
= 70 + 52 + 50 + 84.5
= 256.5 cm
2 Answer(s): (a) (2
s + 3) cm; b) 256.5 cm
2