Question

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

Answer 1

Answer:

let one side be x

x+18+10=42

x+28=42

x=14

now,S=a+b+c/2

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

Step-by-step explanation:

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Answer 2

Answer:

Perimeter of triangle = side + side + side

42 = 18 + 10 + x

42 = 28 + x

42 - 28 = x

14 = x

Area of triangle is by herons formula where s = a+ b + c/2

s = 18+10+14/2

s = 21

putting value

area of triangle is equal to

=root 21( 21-18)(21-14)(21-10)

= root 21× 3×7×11

=21root 11