Question

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

Answer 1

Answer:

69.64 sq. cm

Step-by-step explanation:

P = 42 cm

Given triangle ABC

AB = 18 cm

BC = 10 cm

AC = ?

P = AB + BC + AC

42 = 18 + 10 + AC

AC = 14 cm

Heron's Formula:

s = (a+b+c)/2

s=42/2=21

area=[s(s-a)(s-b)(s-c)]^(1/2)

area=[21(21-18)(21-10)(21-14)]^(1/2)

area=[21x3x11x7]^(1/2)

area=69.69 sq. cm  (XD what a coincidence!!)