Question

find the area of triangle whose sides are 3cm, 4cm, 5cm.

Answer 1

This can be find out by using Heron's Formula:-
$\sqrt{s(s - a)(s - b)(s - c)}$
$where \: s = sum \: of \: all \: sides \: \: \\ \ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \div 2$
then first find out s :-

$3cm + 4cm + 5cm \div 2$
$12 \div 2 \: = 6cm$
Now put values in Formula:-
$\sqrt{s(s - a)(s - b)(s - c)}$
$\sqrt{6(6 - 3)(6 - 4)(6 - 5)}$
$\sqrt{6(3)(2)(1)}$
By taking common:-
$6 \sqrt{1}$
Final Answer :-. 14.69 Approx.

Answer 2

We have a = 3 cm, b = 4 cm and c = 5 cm.

       S = a + b + c /2

        or s = 3 + 4 + 5 / 2 = 12 /2 = 6

By using heron's formula we have

    Area of triangle = √s(s -a)(s-b)(s-c)

          Area = √6(6-3)(6-4)(6-5)

                    = √6 x 3 x 2 x 1 = √36 = 6 cm