9.50 Chapter 9
15. In the figure, ABCDE + PQRST. If AB = 18 cm, AE = 24 cm,
BC = 30 cm, PQ = (x - 5) cm, PT = x cm and QR = (x + y) cm,
find the values of x and y.
16. A and B are a pair of similar quadrilaterals. The lengths of the
four sides of quadrilateral A are 2 cm, 3 cm, 5 cm and 6 cm,
while the length of the shortest side of quadrilateral B is 4 cm.
Find the perimeter of quadrilateral B.
17. Refer to the figure. Determine whether ABCD + EFGH
is true.
18. In the figure, PQRS and ABCD are rectangles. Determine
whether the two rectangles are similar.
Level 3
19. P and Q are a pair of similar quadrilaterals. The lengths of the four
sides of quadrilateral P are x cm, 7 cm, y cm and 15 cm, while the
length of the longest side of quadrilateral Q is 7.5 cm. It is given
that x is an integer less than 7, and y is an integer greater than 7 but
less than 15. If the perimeter of quadrilateral Q is 21 cm, find all
possible set(s) of values of x and y.
20. There are 100 identical square cards. Ken uses 4 of the cards to
form the figure shown on the right. Mary wants to use these cards to
form another figure with the same shape as the figure shown, but of
a greater size. At least how many cards does Mary need?
A E
T
S
R
Q
P
B
C
D
18 cm
24 cm
30 cm
(x + y) cm
(x - 5) cm
x cm
A
E H
D
B C F G
60°
6 cm
4 cm
3 cm
7 cm
➥ Example 18
A
B C
S
P
R
Q
D
3 cm
3 cm
20 cm
3 cm 12 cm
3 cm