Find the area of the parallelogram whose length is 60 cm and width is 25 cm and one diagonal is 45 cm is?

200\(\sqrt{26}\) cm²

Semi - perimeter (s) of ΔABC = \(\frac{60 + 45 + 25}{2}\) = 65

Now,

Area of ΔABC = \(\sqrt {s × (s - a)(s - b)(s - c)}\)

                     = \(\sqrt {65 × (65 - 45 )(65 - 25)(65 - 60)}\)

                     = \(\sqrt {65 × 5 × 40 × 20}\)

                     = \(\sqrt {5 × 13 × 5 × 5 × 8 × 5 × 4}\)

                     = 100\(\sqrt {26}\)cm²

 Therefore,

Area of Parallelogram = 2 × Area of ΔABC = 2 × 100\(\sqrt {26}\) = 200\(\sqrt {26}\)cm²