In a right-angled triangle ABC, if angle B = 90°, BC = 3 cm and AC = 5 cm, then the length of side AB is
a. 3 cm
b. 4 cm
c. 5 cm
d. 6 cm

Solution:

Given, ABC is a right angled triangle with B = 90°.

The sides BC = 3 cm and AC = 5 cm.

We have to find the length of AB.

By Pythagorean theorem,

AC² = AB² +BC²

5² = AB² + 3²

25 = AB² + 9

AB² = 25 - 9

AB² = 16

Taking square root,

AB = 4 cm

Therefore, the length of AB is 4 cm.

✦ Try This: In a right-angled triangle PQR, if angle Q = 90°, QR = 5 cm and PR = 7 cm, then the length of side PQ is

☛ Also Check: NCERT Solutions for Class 7 Maths Chapter 6

NCERT Exemplar Class 7 Maths Chapter 6 Problem 36

In a right-angled triangle ABC, if angle B = 90°, BC = 3 cm and AC = 5 cm, then the length of side AB is: (a) 3 cm, (b) 4 cm, (c) 5 cm, (d) 6 cm

Summary:

In a right-angled triangle ABC, if angle B = 90°, BC = 3 cm and AC = 5 cm, then the length of side AB is 4 cm

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