PSLEThe figure is made up of two rectangles, FGNL and LMJK, and two right-angled isosceles triangles, GHN and JHM. GF = 8 cm, JK = 5 cm and GN =
p cm. FLK and HNML are straight lines.
- Find the length of FK in terms of p. Give your answer in the simplest form.
- Find the total area of the figure when p = 12.
(a)
Length NM
= 8 - 5
= 3 cm
Length HN =
p cm (Isosceles triangle)
Length MJ
= Length CG
= (
p + 3) cm (Isosceles triangle)
Length FK
=
p +
p + 3
= (2
p + 3) cm
(b)
Area of Rectangle FGLN
= 12 x 8
= 96 cm
2 Length LK
=
p + 3
= 12 + 3
= 15 cm
Area of Rectangle JKLM
= 15 x 5
= 75 cm
2 Area of Triangle GHN
=
12 x 12 x 12
= 72 cm
2 Area of Triangle HJM
=
12 x 15 x 15
= 112.5 cm
2 Total area of the figure
= 96 + 75 + 72 + 112.5
= 355.5 cm
2 Answer(s): (a) (2
p + 3) cm; b) 355.5 cm
2