Question

please answer by solving​

Answer 1

3.

The first three angles are in the ratio 1 : 2 : 3

Let x be the common multiple

Then the angles be x, 2x and 3x

We know that, a quadrilateral has a total angle of 360°

⇒ x + 2x + 3x + 120 = 360

⇒ 6x = 360 - 120

⇒ 6x = 240

⇒ x = 40

∴ the first the angles be 40°, 80° and 120°

∴ the least angle is 40° and the greatest angle is 120°

∴ the required average

= (40° + 120°)/2

= 160°/2

= 80°

Option (a) is correct

4.

Let the length of one side of the square is a m

Then its area = a² square m

At the rate of 10 paise per sqaure m, the total cost of ploughing is given Rs. 360

⇒ a² × 10 paise = Rs. 360

⇒ a² × Rs. 10/100 = Rs. 360

⇒ a² = 360 × 100/10

⇒ a² = 3600

⇒ a = 60

∴ the length of one side of the square is 60 m

∴ its perimeter

= 4 × 60 m

= 240 m

Option (b) is correct