One evening, Kaushik was in a park. Children were playing cricket. Birds were singing on a nearby tree of height 80m. He observed a bird on the tree at an angle of elevation of 45°. When a sixer was hit, a ball flew through the tree frightening the bird to fly away. In 2 seconds, he observed the bird flying at the same height at an angle of elevation of 30° and the ball flying towards him at the same height at an angle of elevation of 60°.

Question 38 (i)

At what distance from the foot of the tree was he observing the bird sitting on the tree?




We need to find distance of bird from foot of the tree. i.e we need to find CB Here, ∠ ABC = 90Β° In right angle triangle ABC tan C = (𝑆𝑖𝑑𝑒 π‘œπ‘π‘π‘œπ‘ π‘–π‘‘π‘’ π‘‘π‘œ π‘Žπ‘›π‘”π‘™π‘’" " 𝐢)/(𝑆𝑖𝑑𝑒 π‘Žπ‘‘π‘—π‘Žπ‘π‘’π‘›π‘‘ π‘‘π‘œ π‘Žπ‘›π‘”π‘™π‘’" " 𝐢) tan C = (" " 𝐴𝐡)/𝐡𝐢 tan 45Β° = πŸ–πŸŽ/π‘ͺ𝑩 1 = 80/𝐢𝐡 CB = 80 m

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.