Question

find the area of a triangle two sides of which are 18 cm and 10 cm and the perimeter is 42 cm.11v21 cm

please give me fast ​

Answer 1

Step-by-step explanation:

let the side which is not given be a

perimeter=sum of all sides

42=18 + 10 + a

∵a=14

semi perimeter= 18+ 10+14/2

s=semi perimeter=21cm

By heron's formula $\sqrt{(s)(s-a)(s-b)(s-c)$

$\sqrt{21(21-18)(21-10)(21-14)$

$\sqrt{21*3*11*7$

$\sqrt{21*21*11$

area = $21\sqrt{11$$cm^{2$

Answer 2

Answer:

let the side which is not given be a

perimeter=sum of all sides

42=18 + 10 + a

∵a=14

semi perimeter= 18+ 10+14/2

s=semi perimeter=21cm

By heron's formula \sqrt{(s)(s-a)(s-b)(s-c)

\sqrt{21(21-18)(21-10)(21-14)

\sqrt{21*3*11*7

\sqrt{21*21*11

area = 21\sqrt{11 cm^{2