Basic concept what to look for similarity of two triangles

1. SIMILARITY (CLASS 10TH )
• When one shape can be changed into another after resizing, flipping,
sliding or turning. We can say two shapes are similar.
Properties of Similar Shapes
• In similar shapes, corresponding angles have the same measure.
• In similar shapes, the lengths of corresponding sides are proportional

2. HOW TO PROVE SIMILARITY
OF TWO TRIANGLES
SSS CONDITION (SIDE-SIDE-SIDE)
CHECK: IF TWO TRIANGLES HAVE THREE PAIRS OF SIDES IN THE
SAME RATIO (SCALE FACTOR), THEN TRIANGLES ARE SIMILAR.
3cm
5cm
4cm
6cm
10cm
8cm
Checking 3/6 = ½
4/8 = ½
5/10= ½
Same
ratio
1/2

3. HOW TO PROVE SIMILARITY OF TWO
TRIANGLES
AAA OR AA CONDITION (ANGLE- ANGLE- ANGLE)
CHECK : If two triangles have at least two of their angles equal, then
triangles are similar.
50
75
75
50
Checking:
Two angles are Same
50 and 75

4. HOW TO PROVE SIMILARITY OF TWO TRIANGLES
• SAS CONDITION (SIDE-ANGLE-SIDE)
Check If two triangles have two pairs of sides in the same ratio and the
included angles are also equal, then the triangles are similar.
Checking 5/10= ½
6cm 3/6 = ½
angle 30 (between sides)
3cm
5 cm
10cm
30
30