Question

The base of an isosceles triangle is 30 cm and the area is 300 sq cm,
find its perimeter

Answer 1

Answer:

Since,

Area of rhombus=

2

1

×d1×d2

⇒216=

2

1

×24×d2

⇒216=12×d2

⇒

12

216

=d2

⇒d2=18cm

So, second diagonal =18cm

As shown in fig. AC=18CM,BD=24CM

Since, diagonals of rhombus bisects each other at right angle.

∴AO=9cm,DO=12cm

In △AOD

AO

2

+DO

2

=AD

2

⇒9

2

+12

2

=AD

2

⇒81+144=AD

2

⇒225=AD

2

⇒AD=15cm

∴ side of rhombus (AD)=15cm

Perimeter of rhombus =4×side

=4×15=60cm

Perimeter of rhombus =60cm

solution