1. Similar Triangles

2. Similar Triangles
TESTS

3. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)

4. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)
(2) Two pairs of corresponding sides are in proportion AND the
included angles are equal (SAS – with ratio a:b)

5. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)
(2) Two pairs of corresponding sides are in proportion AND the
included angles are equal (SAS – with ratio a:b)
(3) All three angles are the same as the three angles in the other (AA)

6. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)
(2) Two pairs of corresponding sides are in proportion AND the
included angles are equal (SAS – with ratio a:b)
(3) All three angles are the same as the three angles in the other (AA)
e.g. Find AD
C
21 cm
E
15 cm
A B
D
24 cm

7. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)
(2) Two pairs of corresponding sides are in proportion AND the
included angles are equal (SAS – with ratio a:b)
(3) All three angles are the same as the three angles in the other (AA)
e.g. Find AD
C DAE  BAC common A
21 cm
E
15 cm
A B
D
24 cm

8. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)
(2) Two pairs of corresponding sides are in proportion AND the
included angles are equal (SAS – with ratio a:b)
(3) All three angles are the same as the three angles in the other (AA)
e.g. Find AD
C DAE  BAC common A
21 cm
E EDA  CBA corresponding' s, BC||DE  A
15 cm
A B
D
24 cm

9. Similar Triangles
TESTS
(1) Corresponding sides are in proportion (SSS – with ratio a:b)
(2) Two pairs of corresponding sides are in proportion AND the
included angles are equal (SAS – with ratio a:b)
(3) All three angles are the same as the three angles in the other (AA)
e.g. Find AD
C DAE  BAC common A
21 cm
E EDA  CBA corresponding' s, BC||DE  A
15 cm
DAE ||| BAC  AA
A B
D
24 cm

10. A A
24 cm 36 cm 15 cm
B C D E

11. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC

12. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC
AD 15

24 36
AD  10cm

13. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC
AD 15

24 36
AD  10cm
In similar shapes;

14. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC
AD 15

24 36
AD  10cm
In similar shapes;
If sides are in the ratio a : b

15. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC
AD 15

24 36
AD  10cm
In similar shapes;
If sides are in the ratio a : b
area is in the ratio a 2 : b 2

16. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC
AD 15

24 36
AD  10cm
In similar shapes;
If sides are in the ratio a : b
area is in the ratio a 2 : b 2
volume is in the ratio a 3 : b 3

17. A A
24 cm 36 cm 15 cm
B C D E
AD AE
 ratio of sides in ||| ' s 
AB AC
AD 15

24 36
AD  10cm
In similar shapes;
Exercise 8H; 2bd, 4ab, 6bc,
If sides are in the ratio a : b
8, 12, 16, 18, 20, 21, 24*
area is in the ratio a 2 : b 2
volume is in the ratio a 3 : b 3