Question

area of a triangle whose sides are 12cm,9.6cm and 7.2cm

Answer 1

${\text{Perimeter of a triangle whose sides are 12 cm, 9}}{\text{.6 cm and 7}}{\text{.2 cm is given by}} \hfill \\ s = \frac{{12 + 9.6 + 7.2}}{2}\,{\text{units = }}\frac{{28.8}}{2}\,{\text{units = 14}}{\text{.4 units}} \hfill \\ \therefore {\text{Area of given triangle = }}\sqrt {s\left( {s - a} \right)\left( {s - b} \right)\left( {s - c} \right)} \,\,\,\left( {{\text{Heron's Formula}}} \right)\, </p><p> \Rightarrow \,A\, = \,\sqrt {14.4\left( {14.4 - 12} \right)\left( {14.4 - 9.6} \right)\left( {14.4 - 7.2} \right)} \hfill \\</p><p>\hfill \\\Rightarrow \,A\, = \,\sqrt {14.4 \times 8.4 \times 4.8 \times 7.2} \hfill \\ </p><p> \Rightarrow \,A\, = \,\sqrt {4180.3776} \hfill \\</p><p>$

Answer 2

Answer:

Answer = 34.56cm²

Step-by-step explanation:

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Let 12 cm =a;

9.6 cm = b;

7.2 cm = c;.

therefore,

Perimeter = (a+b+c)cm

= (12+9.6+7.2)cm

= 28.8 cm

now,

Semi perimeter = 28.2/2

= 14.4cm

therefore,

Area = √s(s-a)(s-b)(s-c)

= √14.4 (14.4-12) (14.4-9.6) (14.4-7.2)

= √14.4 × 2.4 × 3.8 × 7.2

= √ 1194.3936

= 34.56 cm²..........

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