Question

Find the area of an isosceles triangle whose base is 8cm and perimeter 20cm.​

Answer 1

Answer:

8√5

Step-by-step explanation:

Perimeter of an isosceles ∆

= Sum of all sides (a+b+c)

= 20cm

The base(non- equal side) measure

= 8cm

let the other two equal sides be

= x

According to the question

• x + x + 8 = 20
• 2x = 20-8
• x = 12/2
• x = 6cm

Therefore,

Area of the isosceles triangle

= _______________

√s (s - a) (s - b) (s - c)

Here, a = 6cm, b = 6cm and c = 8cm

s = semi- perimeter = 20/2

= 10cm

_______________________

√10 (10-6) (10-6) (10-8)

______________________

√ 10 × 4 × 4 × 2

_____________________

4 √ 2×5× 2

4×2 √5

8√5