Question

ABCD is a quadrilateral in which P, Q, R and Sare
mid-points of the sides AB, BC, CD and DA
(see Fig 8.29). AC is a diagonal. Show that:
1
(1) SRI AC and SR = AC
2
I) PQ=SR
(1) PQRS is a parallelogram.

Answer 1

Step-by-step explanation:

The Midpoint Theorem states that the segment joining two sides of a triangle at the midpoints of those sides is parallel to the third side and is half the length of the third side.

(i) In △DAC , S is the mid point of DA and R is the mid point of DC. Therefore, SR∥AC and SR= 1/2

AC.By mid-point theorem.

(ii) In △BAC , P is the mid point of AB and Q is the mid point of BC. Therefore, PQ∥AC and PQ= 1/2

AC.By mid-point theorem. But from (i) SR= 1/2

AC therefore PQ=SR

(iii) PQ∥AC & SR∥AC therefore PQ∥SR and PQ=SR. Hence, a quadrilateral with opposite sides equal and paralle is a parallelogram. Therefore PQRS is a parallelogram.