Question

Find the area of the triangluar field whose sides are $39m,25m$ and $56m$ respectively.

• A. $420m^2$
• B. $520m^2$
• C. $820m^2$
• D. $320m^2$

Answer 1

The correct option is A $420m^2$

$s=(25+39+56)÷2$
$=60m$

Area $=\sqrt{s(s-a)(s-b)(s-c)}{m}^2$

$=\sqrt{60(60-39)(60-25)(60-56)}$

$=\sqrt{60\times 35\times 21\times 4}$

$=\sqrt{(5\times 3\times 4)\times (5\times 7)\times (7\times 3)\times 4}$

$=(4\times 3\times 5\times 7)m^2=420m^2$