Question

an isoscale triangle had perimeter 30 cm and each equal side is 12 cm find the area of triangle​

Answer 1

Answer:

Given ,

perimeter = 30 cm

length of each equal side = 12 cm

length of unequal side = 30 - 2( 12)

                                      = 30 - 24   = 6 cm

Now to find the height , we draw the altitude from angle A as shown in the attachment.

The altitude makes a 90° with BC which means it perpendicularly bisects BC.

Lets take the point where the altitude meets BC as D .

DC = DB = 3 cm

Length of AD = ?

AD = √12² - 3²

     = √144 - 9

     = √135

     = 11.618 cm                        [ approx. ]

area of triangle = 1/2 bh

b = 6 cm

h = 11.618

area = 1/2 × 6 × 11.618

        = 34.854 cm²

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