Question

5. In the given figure, ABC is right-angled at B and cotA=3/4​

Answer 1

Correct Question :-

In the given figure, ∆ABC is right angled at B and cotA = 4/3. If AC = 10cm, then the length of AB is ?

Given :-

• ∆ABC is right angled at B
• cotA = 4/3
• AC = 10cm

ToFind :-

• Length of AB

Solution:-

• cotA = 3/4 = AB/BC
• AB/BC = 3/4
• AB:BC = 3:4

Let,

• AB = 3x
• BC = 4x

In right angle ∆ABC,

→ AC² = AB² + BC²

→ 10² = 3x² + 4x²

→ 100 = 9x² + 16x²

→ 25√x² = 100

→ x² = 4

→ x = 2

→ AB = 3x = 6cm

★ Hence, the length of AB is 6cm