NTA Abhyas JEE Main2020MathematicsCirclePractice
Let triangle A B C is right-angled at A . The circle with centre A and radius A B cuts B C and A C internally at D and E respectively. If B D = 20 units and D C = 16 units, then the length A B is equal to
Options
- A6 21 units
- B6 10 units
- C300 units
- D18 units
Correct answer
B. 6 10 units
Step-by-step solution
b 2 + r 2 = 36 2 … i Also C D ⋅ C B = C E ⋅ C X 16 ⋅ 36 = b - r b + r ∴ b 2 - r 2 = 16 ⋅ 36 From i and i i 2 b 2 = 36 36 + 16 = 36 ⋅ 52 b 2 = 36 ⋅ 26 ⇒ b = 6 26 units and r = 36 2 - 36 26 = 6 10 units