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Find the area of a triangle …

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Find the area of a triangle two sides of which are 18c.m. and 10c.m. and perimeter is 42 c. m.

Posted by Arun Kurmi 4 years, 2 months ago

CBSE > Class 09 > Mathematics

2 answers

Gaurav Seth 4 years, 2 months ago

Given,
Side a=18cm
Side b=10cm
Perimeter=42cm=a+b+c
:. Putting value
42=18+10+c
42=28+c
42-28=c
14=c
Now,
S=(a+b+c)/2
:. Putting value
S=42/2
S=21
Now according to Heron's formula-
Area of a triangle
=√{s(s-a)(s-b)(s-c)}
:. Putting value
=√{21(21-18)(21-10)(21-14)}
=√{21(3)(11)(7)}
=√4851
=21√11cm²

0Thank You

Disha Matta 4 years, 2 months ago

It's 74.5cm2

1Thank You

ANSWER

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CBSE > Class 09 > Mathematics