Question

2. In A ABC, <B = 90°, AB= 13cm, AC= 21cm
BC=--------​

Answer 1

by pythagorous theorem,

21²=13²+BC²

441-169=BC²

272=BC²

BC=4√17

Answer 2

Step-by-step explanation:

• Here, In ∆ ABC
• Angle B = 90°
• So, ∆ABC IS A RIGHT ANGLE TRIANGLE.
• Now, AB = 13 cm
• AC = 21 cm
• BC = ?
• By pythagores theorem ,
• Hypotenuse^2 = Base^2 + Perpendicular^2
• AC ^2 = BC ^2 + AB^2
• 21^2 = BC^2 + 13^2
• 441 = BC^2 + 169
• BC^2 = 441-169
• BC = √272=16.5cm (approx)