PSLEThe figure is made up of two rectangles, JKRP and PQMN, and two right-angled isosceles triangles, KLR and MLQ. KJ = 13 cm, MN = 7 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 = 20.
(a)
Length RQ
= 13 - 7
= 6 cm
Length LR =
s cm (Isosceles triangle)
Length QM
= Length CG
= (
s + 6) cm (Isosceles triangle)
Length JN
=
s +
s + 6
= (2
s + 6) cm
(b)
Area of Rectangle JKPR
= 20 x 13
= 260 cm
2 Length PN
=
s + 6
= 20 + 6
= 26 cm
Area of Rectangle MNPQ
= 26 x 7
= 182 cm
2 Area of Triangle KLR
=
12 x 20 x 20
= 200 cm
2 Area of Triangle LMQ
=
12 x 26 x 26
= 338 cm
2 Total area of the figure
= 260 + 182 + 200 + 338
= 980 cm
2 Answer(s): (a) (2
s + 6) cm; b) 980 cm
2