Question

9. A parallelogram has sides 15 cm and 7 cm long. The
length of one of the diagonals is 20 cm. The area of the
parallelogram is:
a. 42 cm2 b. 60 cm2 c. 84 cm2 d. 96 cm2​

Answer 1

Answer:

84 cm^2

Step-by-step explanation:

hope it is correct

Answer 2

Answer:

84cm^2

Step-by-step explanation:

Using heron's formula

S= 15+7+20/2 = 21cm

area of triangle ABC =

$\sqrt{21(21 - 20)(21 - 7)(21 - 15)}$

$\sqrt{21 \times 1 \times 14 \times 5}$

= 42cm^2

Area of parallelogram ABCD = 42×2

= 84cm^2