9.42 Chapter 9
In the figure, ABCD + EFGH. Find x and y.
a ABCD + EFGH
` +BAD = +FEH
= 92c
In 3ABD,
+BAD + +ABD + +ADB = 180c �+ sum of 3�
92c + 50c + x = 180c
x = 38c
a ABCD + EFGH
` EH
AD = FG
BC
y
6 = 6
9
y = 9
66#
= 4
A
D
B C
x
50°
9
6
E
Hy
92°
F G6
Level 1
Example 16
Solution Diagram Clue E
A
H
D
B C
x y
50° 92°
9 F G6
6
Corresponding angles
are equal.
◀ Corresponding sides
are proportional.
◀
We learnt that in two similar figures, their corresponding angles are
equal, and their corresponding sides are proportional. Obviously, if two
figures have all these properties, then they are similar. However, if two
figures do not have some of these properties, then they are not similar.
Some examples are given below.
e.g. (a) The pair of the figures below does not have the property
'corresponding angles are equal'. They are not similar.
100°
105°
110°
65° 80° 70° 75°
115°
P
C
D
A
B Q S
R
+A is not equal to any angle of PQRS.
In the figure, ABCD + EFGH.
Find x and y.
16
Instant Drill
➥ Ex 9D 5, 6
D
A
B C
x
45°
5
10
H
E
F G
y
100°
8