If A(3, 5), B(– 5, – 4), C(7, 10) are the vertices of a parallelogram taken in order, then the co-ordinates of the fourth vertex are: -Maths 9th

1 Answer

Answer :

(c) RhombusCo-ordinates of P are \(\bigg(rac{-1-1}{2},rac{-1+4}{2}\bigg)\)i.e, \(\big(-1,rac{3}{2}\big)\)Co-ordinates of Q are \(\bigg(rac{-1+5}{2},rac{4+4}{2}\bigg)\)i.e, (2, 4)Co-ordinates of R are \(\bigg(rac{5+5}{2},rac{4-1}{2}\bigg)\)i.e, \(\big(5,rac{3}{2}\big)\)Co-ordinates of S are \(\bigg(rac{-1+5}{2},rac{-1-1}{2}\bigg)\)i.e, (2, -1)Now,⇒ PQ = QR = RS = SP ⇒ All sides are equalAlso, PR = \(\sqrt{(5+1)^2+\big(rac{3}{2}-rac{3}{2}\big)^2}\) = \(\sqrt{36}\) = 6SQ = \(\sqrt{(2-2)^2+(4+1)^2}\) = \(\sqrt{25}\) = 5⇒ PR ≠ SQ ⇒ Diagonals are not equal ⇒ PQRS is a rhombus.

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