PSLEThe figure is made up of two rectangles, FGNL and LMJK, and two right-angled isosceles triangles, GHN and JHM. GF = 11 cm, JK = 6 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 = 19.
(a)
Length NM
= 11 - 6
= 5 cm
Length HN =
p cm (Isosceles triangle)
Length MJ
= Length CG
= (
p + 5) cm (Isosceles triangle)
Length FK
=
p +
p + 5
= (2
p + 5) cm
(b)
Area of Rectangle FGLN
= 19 x 11
= 209 cm
2 Length LK
=
p + 5
= 19 + 5
= 24 cm
Area of Rectangle JKLM
= 24 x 6
= 144 cm
2 Area of Triangle GHN
=
12 x 19 x 19
= 180.5 cm
2 Area of Triangle HJM
=
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
p + 5) cm; b) 821.5 cm
2