Question

If the area of a semi-circular field is 15400 sq m, then perimeter of the eld is: [1] (a) 160$\sqrt{2}$m (b) 260$\sqrt{2}$m (c) 360$\sqrt{2}$m (d) 460$\sqrt{2}$m

Answer 1

(D)460 root 2 i guess this is the anwer

Answer 2

Given :----

• Area of semi-circle = 15400m² .

To Find :---

• Perimeter of Semi-circle ..

Formula used :-----

• Area of semi-circle = πr²/2
• Perimeter of semi-circle = πr + 2r ( Diamter length will also add in perimeter remember this) .

Calculation :------

→ πr²/2 = 15400

→ πr² = 15400×2

→ r² = 15400×2 × 7/22

→ r² = 7×7×100×2

→ r = 7×10×√2 = 70√2 m .

_______________________

Now, perimeter = πr + 2r ,

putting values we get,

→ perimeter = 22/7 × 70√2 + 2(70√2)

→ perimeter = 22×10√2 + 140√2

→ perimeter = 220√2 + 140√2

→ perimeter = 360√2 m .

Hence , perimeter of semi-circle will be 360√2m .

(Hope it helps you) ..