Question

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

Answer 1

Step-by-step explanation:

Area of triangle

s(s−a)(9−b)(s−0)

Here, s is the semi- perimeter,

and a,b,c are the sides of the triangle

Given a=18 cm, b=10 cm

and perimeter =42 cm

semi- perimeters=

2

perimeter

=

2

42

s=21cm.

Area of triangle

∴c=42−(18+10)cm =14 cm

∴ Area of triangle=

21.(21−18)(21−10)(21−14)

=

21.3.7.11

cm

2

=

3×7×3×7×11

cm

2

=

(3×7)

2

×11

cm

2

=21

11

cm

2

∴ Thus, the required area of the triangle is 21 ✓11 cm ².

hopefully it will work ☺️☺️

Answer 2

perimeter of triangle = a + b + c

42= 10 + 18 + x

42 = 28+x

42-28=x

x = 14