5.1.5 Similar triangles ➤152 162➤➤
The trianglesABCandDEFare similar.
BAC EDFFigure 5.5
IfBC= 5 .0cm,AB= 4 .0cm,AC= 3 .0cmandFE= 3 .0 cm find:
(i) the ratio between the sides of the two triangles;
(ii) the lengths of the remaining sides,DF,DE.What is the angleBAC?
5.1.6 The intercept theorem ➤153 162➤➤
Find the missing length,DB, in each of the figures below:
(^45)
6
1.5
2
3
A
E
E
C
C
A
B
B
(i) (ii)
D
D
Figure 5.6
5.1.7 The angle bisector theorem ➤153 163➤➤
IfADbisects the angleA, find the length ofDB.
1 2
C 9 /10
A
D B
Figure 5.7