PSLEThe figure is made up of two rectangles, JKRP and PQMN, and two right-angled isosceles triangles, KLR and MLQ. KJ = 11 cm, MN = 6 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 = 19.
(a)
Length RQ
= 11 - 6
= 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
= 19 x 11
= 209 cm
2 Length PN
=
s + 5
= 19 + 5
= 24 cm
Area of Rectangle MNPQ
= 24 x 6
= 144 cm
2 Area of Triangle KLR
=
12 x 19 x 19
= 180.5 cm
2 Area of Triangle LMQ
=
12 x 24 x 24
= 288 cm
2 Total area of the figure
= 209 + 144 + 180.5 + 288
= 821.5 cm
2 Answer(s): (a) (2
s + 5) cm; b) 821.5 cm
2