Math, asked by kundan8389, 10 months ago

Area of an isosceles triangle whose base is 18 cm and one of it's equal is 15 cm

Answers

Answered by gouravkumarmodak
3

Step-by-step explanation:

In the above isosceles triangle

AB= 15cm

AC= 15cm

BC= 18cm

BD=18÷2=9cm

AD is the altitude.

according to Pythagorean Theorem

(AD)^2 + (BD)^2 = (AB)^2

(AD)^2 + (9) ^2 = (15) ^2

(AD)^2 + 81 = 225

(AD)^2 = 225 - 81

(AD)^2 = 144

Therefore, AD = √144 = 12cm

Now,

Area of the triangle

= 1/2 × base × height

=1/2 × BC × AD

=(1/2 × 18 × 12)

= 108 sq cm

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