PSLEThe figure is made up of two rectangles, JKRP and PQMN, and two right-angled isosceles triangles, KLR and MLQ. KJ = 14 cm, MN = 9 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 = 18.
(a)
Length RQ
= 14 - 9
= 5 cm
Length LR =
s cm (Isosceles triangle)
Length QM
= Length CG
= (
s + 5) cm (Isosceles triangle)
Length JN
=
s +
s + 5
= (2
s + 5) cm
(b)
Area of Rectangle JKPR
= 18 x 14
= 252 cm
2 Length PN
=
s + 5
= 18 + 5
= 23 cm
Area of Rectangle MNPQ
= 23 x 9
= 207 cm
2 Area of Triangle KLR
=
12 x 18 x 18
= 162 cm
2 Area of Triangle LMQ
=
12 x 23 x 23
= 264.5 cm
2 Total area of the figure
= 252 + 207 + 162 + 264.5
= 885.5 cm
2 Answer(s): (a) (2
s + 5) cm; b) 885.5 cm
2