PSLEThe figure is made up of two rectangles, JKRP and PQMN, and two right-angled isosceles triangles, KLR and MLQ. KJ = 10 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 = 13.
(a)
Length RQ
= 10 - 6
= 4 cm
Length LR =
s cm (Isosceles triangle)
Length QM
= Length CG
= (
s + 4) cm (Isosceles triangle)
Length JN
=
s +
s + 4
= (2
s + 4) cm
(b)
Area of Rectangle JKPR
= 13 x 10
= 130 cm
2 Length PN
=
s + 4
= 13 + 4
= 17 cm
Area of Rectangle MNPQ
= 17 x 6
= 102 cm
2 Area of Triangle KLR
=
12 x 13 x 13
= 84.5 cm
2 Area of Triangle LMQ
=
12 x 17 x 17
= 144.5 cm
2 Total area of the figure
= 130 + 102 + 84.5 + 144.5
= 461 cm
2 Answer(s): (a) (2
s + 4) cm; b) 461 cm
2