Question 19 — slide 51

Question 19 — slide 52

Question 19 — slide 53

Question 19 — slide 54

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Teachoo · Class 10 Explore Class 10

Transcript

Question 19 Assertion (A): If three vertices of a parallelogram taken in order are (−1, −6), (2, −5) and (7, 2), then its fourth vertex is (4, 1). Reason (R): Diagonals of a parallelogram bisect each other. Checking Assertion Let the parallelogram be PQRS With fourth vertex as S Since it’s a Parallelogram It’s Diagonals bisect each other Therefore, P (-1, -6) Q (2, -5) R (7, 2) O S (x, y) Mid point of PR = Mid point of QS ((−1 + 7)/(2),(−6 + 2 )/(2))=((2 + 𝑥)/(2),(−5 + 𝑦)/(2)) ((𝟔)/(𝟐),(−𝟒)/(𝟐))=((𝟐 + 𝒙)/(𝟐),(−𝟓 + 𝒚)/(𝟐)) Comparing x-coordinate (6)/(2)=(−2 + 𝑥)/(2) 6 = 2 + x 6 – 2 = x x = 4 ∴ Coordinates of point S is (4, 1) Comparing y-coordinate (−4)/(2)=(−5 + 𝑦)/(2) –4 = –5 + y –4 + 5 = y y = 1 Since the coordinate of the 4^(th) vertex is (4, 1) Thus, Assertion is true Checking Reason Reason (R): Diagonals of a parallelogram bisect each other. This is always true Thus, Reason is true Is Reason correct explanation for Assertion? We use Reason to find coordinates in Assertion Therefore, Reasoning is correct explanation for Assertion So, Assertion is true Reasoning is true and, Reasoning is correct explanation for Assertion So, the correct answer is (a)

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CA Maninder Singh

CA Maninder Singh is a Chartered Accountant qualified since 2010 and an educator teaching since 2006. At Teachoo, he draws on his accounting and tax experience to explain Accounts, Income Tax and GST through step-by-step lessons and practical examples.

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