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Ex 6.3, 10 - Find smallest square number that is divisible by 8, 15 20

Ex 6.3, 10 - Chapter 6 Class 8 Squares and Square Roots - Part 2
Ex 6.3, 10 - Chapter 6 Class 8 Squares and Square Roots - Part 3


Transcript

Ex 6.3, 10 Find the smallest square number that is divisible by each of the numbers 8, 15 and 20.Smallest square number divisible by 8, 15, 20 = L.C.M of 8, 15, 20 Or Multiple of L.C.M Finding L.C.M of 8, 15, 20 L.C.M of 8, 15, 20 = 2 × 2 × 2 × 3 × 5 = 4 × 6 × 5 = 4 × 30 = 120 Checking if 120 is a perfect square We see that, 120 = 2 × 2 × 2 × 3 × 5 Here, 2, 3 & 5 do not occur in pairs ∴ 120 is not a perfect square So, we multiply by 2, 3 and 5 to make pairs So, our number becomes 120 × 2 × 3 × 5 = 2 × 2 × 2 × 3 × 5 × 2 × 3 × 5 3600 = 2 × 2 × 2 × 2 × 3 × 3 × 5 × 5 Now, it becomes a perfect square. So, required number is 3600

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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 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.