Page 173 - Start Up Mathematics_7

Right-Angled Triangle and Pythagoras Property A
(or Pythagoras Theorem)
In a right-angled triangle, the side opposite the Hypotenuse

right angle is known as hypotenuse and the Perpendicular
other two sides containing the right angle are
called its legs or simply referred to as base and B Base C
perpendicular.

Pythagoras Property
In a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares

of the other two sides. Therefore, in a right-angled ∆ ABC having right angle at B, we have
2
2
2
AC = AB + BC .
Maths Lab Activity
Maths Lab Activity
Objective: To verify Pythagoras property, i.e., to verify in a right-angled triangle, the square
of the hypotenuse is equal to the sum of the squares of the legs.
Measure the lengths of the sides of the following triangles and complete the table:

P

A

B C Q R

S. No. Triangle Measure of length Compute Observation
2
2
2
2
2
1. ∆ ABC AB = ________ AB , BC , CA 2 Is AB + BC = CA ?
2
BC = ________ and AB + BC 2 Yes No
CA = ________
2
2
2
2
2
2. ∆ PQR PQ = ________ PQ , QR , RP 2 Is PQ + QR = RP ?
2
QR = ________ and PQ + QR 2 Yes No
RP = ________
If the observation in the above cases is yes, then Pythagoras property is verified.
Caution: If the measure of sides is not accurate, it can lead to wrong result.

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