Explanation:

In the given ||gm P and Q are the mid points of the sides BC and CD respectively, and AC and BD are the diagonals.
In ΔABC, AP is a median and similarly in ΔADC, AQ is a median.
Now, since median divides the triangle into two equal areas, area of ΔABP = 1/2 area of ABC = 1/2 × 1/2 area of the ||gm ABCD
[Since the diagonal AC divides of the ||gm into two equal areas]
= 1/4 of area of ||gm ABCD    ...(1)
Similarly, area of ΔADQ
= 1/4 of area of ||gm ABCD   ...(2)
Now, in ΔBCD, if we join the mid-points P and Q, the area of the triangle thus formed (ΔPCQ) will be 1/4 of the area of the ΔBCD as per the mid-point theorem.
∴ Area of ΔPCQ = 1/4 of area of ΔBCD