Congruence and Similarity (II) 9.43
Refer to the figure. It is given that the sum of interior
angles of quadrilateral ABCD is 360c. Explain why it
is impossible for quadrilaterals ABCD and EFGH to be
similar figures.
50°
60° 110°
A
D
C
B
130°
G
F
H
E
In ABCD ,
+BAD + +ABC + +BCD + +ADC = 360c
+BAD + 60c + 110c + 50c = 360c
+BAD = 140c
a +FEH = 130c
` +FEH is not equal to any angle of ABCD.
` It is impossible for ABCD and EFGH to be similar
figures.
Level 1
Example 17
Solution
ABCD and EFGH do not have
the property 'corresponding
angles are equal'.
◀
Refer to the figure. It is given that the sum of interior angles of
quadrilateral ABCD is 360c . Explain why it is impossible for
quadrilaterals ABCD and EFGH to be similar figures.
A B C D
110°
70°
100°
75°
E F GH
17
Instant Drill
➥ Ex 9D 7
(b) The pair of the figures below does not have the property
'corresponding sides are proportional'. They are not similar.
1
1
2
2
3
2
1 1
W
Z
X
Y
HE
F G
EF
WX = FG
XY = EH
WZ = 1
2, but GH
YZ = 1
3.