Question

Draw parallelogram ABCD with the following measurements and calculate its area.
AB = 5 cm, BC = 4 cm, AC = 7 cm.

Answer 1

Area of parallelogram ABCD$=2\times ar△ABC$

$ar△ABC=\sqrt{s(s-a)(s-b)(s-c)}$

$s=\frac{a+b+c}{2}=\frac{5+4+7}{2}=8㎝$

$ar△ABC=\sqrt{8\times 3\times 4\times 1}=9.80㎠$

$\therefore$ Area of parallelogram ABCD$=2\times 9.80=19.60㎠$