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Transcript

Ex 9.1, 4 Find the missing values: (a) Base = 15 cm, Height = ?, Area = 87 cm2 Height = h = ? Base = b = 15 cm Given, Area of ∆ABC = 87 cm2 1/2 × b × h = 87 𝟏/𝟐 × 15 × h = 87 h = 87 × 2/15 h = 29 × 2/5 h = 𝟓𝟖/𝟓 h = 11.6 cm ∴ Height is 11.6 cm (a) Base = ?, Height = 31.4 mm, Area = 1256 mm2 Height = h = 31.4 mm Base = b = ? Given, Area of ∆ABC = 1256 mm2 1/2 × b × h = 1256 𝟏/𝟐 × b × 31.4 = 1256 b = 1256 × 2/31.4 b = 1256 × 2 × 1/31.4 b = 1256 × 2 × 𝟏𝟎/(𝟑𝟏𝟒 ) b = 1256 × 10/157 b = 1256/157 × 10 b = 8 × 10 b = 80 mm (a) Base = 22 cm, Height = ?, Area = 170.5 cm2 Height = h = ? Base = b = 22 cm Given, Area of ∆ABC = 170.5 cm2 1/2 × b × h = 170.5 𝟏/𝟐 × 22 × h = 170.5 11 × h = 170.5 h = (𝟏𝟕𝟎.𝟓)/𝟏𝟏 h = 1705/(11 × 10) h = 155/10 h = 15.5 cm ∴ Height is 15.5 cm

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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.