Question

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

Answer 1

Answer:

Step-by-step explanation:

perimeter = 42cm

18+10+x = 42

therefore,

x= 42-18-10 = 14 cm

now,

S = perimeter/2 = 42/2 = 21cm

using herons formulae,

Ar(ABC)= $\sqrt{S(S-A)(S-B)(S-C)}$               [Where S is Semi perimeter and                            

                                                                       A,B ,C    are the sides of triangle]

Therefore,

$ar(ABC) = \sqrt{21(21-18)(21-10)(21-14)}$

$ar(ABC)=\sqrt{21(3)(11)(7)}$

$ar(ABC)=21\sqrt{11}$ $cm^{2}$

Hope you got it!

Answer 2

Answer:

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