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 = 19.
(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
= 19 x 10
= 190 cm
2 Length PN
=
s + 4
= 19 + 4
= 23 cm
Area of Rectangle MNPQ
= 23 x 6
= 138 cm
2 Area of Triangle KLR
=
12 x 19 x 19
= 180.5 cm
2 Area of Triangle LMQ
=
12 x 23 x 23
= 264.5 cm
2 Total area of the figure
= 190 + 138 + 180.5 + 264.5
= 773 cm
2 Answer(s): (a) (2
s + 4) cm; b) 773 cm
2