Question

An isoscles triangle has perimeter 30cm and each of the equal sides is 12cm.find the area of triangle

Answer 1

Answer:

area of triangle

1/2×length×breadth

1/2×12×30

30×6

180

Answer 2

Given :

• Each equal side = 12cm
• Perimeter = 30cm

To Find :

• Area of Triangle

Solution :

$\longrightarrow\tt{Let\:third\:side=c}$

$\longrightarrow\tt{12+12+c=30}$

$\longrightarrow\tt{24+c=30}$

$\longrightarrow\tt{c=30-24}$

$\longrightarrow\tt\bold{c=6cm}$

Now :

$\longrightarrow\tt{s=\dfrac{a+b+c}{2}}$

$\longrightarrow\tt{s=\dfrac{12+12+6}{2}}$

$\longrightarrow\tt{s=\cancel\dfrac{30}{2}=15cm}$

$\longrightarrow\tt{Area=\sqrt{s(s-a)(s-b)(s-c)}}$

$\longrightarrow\tt{\sqrt{15(15-12)(15-12)(15-6)}}$

$\longrightarrow\tt{\sqrt{15\times{3}\times{3}\times{9}}}$

$\longrightarrow\tt{3\times{3}\sqrt{15}}$

$\longrightarrow\tt\boxed{9\sqrt{15}{cm}^{2}}$

So , The Area of Triangle is 9√15cm²..