Question

using her on formula find the area of a triangle whose two sides are 60 and 80 and the perimeter is 260.

Answer 1

1)
perimeter =180cm

18+80+third side =180
98+ x =180

x=180-98

x=82 cm

2)take all sides like
a=18,b=80,c=82
s= perimeter/2 = 180/2=90

s-a =90-18=72
s-b=90-80=10
s-c=90-82=8

area = root s(s-a)(s-b)(s-c)
= root 90*72*10*8
=root 90*90*8*8
=720 square cm

3) shortest side =base =18 cm

area =720

1/2*base* altitude(h)= 720

h= 720*2/18
h=80cm

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Answer 2

sides of triangle =60 and 80
perimeter =260
third side =260-80-60
=120

therefore by herons formula
area=root 130(130-60)(130-80)(130-120)
root(130)(70)(50)(10)
root(10×13×7×10×5×10×10)
10×10root(7×5×13)
100root(455)