Question

find the are of triangle teo sides of which are 18 cm and 10 cm and the petinetere is 42 cm​

Answer 1

Answer:

Two sides length are given, we need to figure out the length of this side.

⇒Let x be length of third side

⇒Perimeter =42 cm

⇒18+10cm+x=42

⇒x=42−28=14 cm

⇒2s=42

⇒s=21 cm

⇒a=18,b=10,c=14

⇒A=

s(s−a)(s−b)(s−c)

⇒

21(21−18)(21−10)(21−14)

=

21×3×11×7

⇒A=21

11

cm

2