Question

The equal sides of the isosceles triangle are 12cm perimeter is 30cm. Find area​

Answer 1

Answer: (a) 9√15 cm²

Step-by-step explanation: Perimeter of isosceles triangle=30cm

Length of equal sides=12cm

Let third side of triangle=xcm

According to problem,

x+12+12=30

x+24=30

x=30−24

x=6

∴ Third side of triangle=6cm

Using Heron's formula

Area of triangle=

√s(s−a)(s−b)(s−c) sq. units

where,

s = a+b+c / 2

s = 30 / 2

s = 15

Area of triangle=

√15(15−12)(15−12)(15−6) cm²

= √15×3×3×9 cm²

= 3×3×√15 cm²

= 9√15 cm²

∴ Area of triangle = 9√15 cm².

Answer 2

ANSWER

36CM SQUARE

GIVEN

equal sides-----) 12cm

perimeter------) 30cm

SOLUTION

let unknown side be x

then,

2a+b= perimeter

12+12+x=30

24+x=30

x=30 - 24

x=6

FIRST SIDE-------) 12CM

SECOND SIDE-----) 12CM

THIRD SIDE-------) 6CM

NOW, WE FIND AREA

AREA= 1/2(Base×height)

1/2(12×6)

12×6/2

--------)36

AREA ------) 36CM SQUARE