Explanation

Area of circle = πr²  

Circumference = 2πr

Given: Area = 275 m²

1. Find radius r:

πr² = 275

r² = 275 / π = 275 / 3.1416 ≈ 87.54

r = √87.54 ≈ 9.356 m

2. Find circumference:

C = 2πr = 2 × 3.1416 × 9.356 ≈ 58.78 m

Last verified on 05-08-2026

Explanation

We can use tan to find the height.

Given:

Person's height = 1.6 m 

Distance from tower = 20 m

Angle of elevation = 45°

Let h = height of tower above the person's eye level.

In the right triangle:

tan(45°) = opposite / adjacent = h / 20

We know tan(45°) = 1

So: 

1 = h / 20

h = 20 m

This is the height from eye level to top of tower.

Total height of tower = h + person's height

= 20 m + 1.6 m 

= 21.6 m

Last verified on 05-08-2026

Explanation

Perimeter of rectangle = 2 × (Length + Width)

Given: 

Length = 58.7 

Width = 23.2

Perimeter = 2 × (58.7 + 23.2)

= 2 × 81.9

= 163.8

Last verified on 05-08-2026

Explanation

LCM of 5, 7, 10, 12 = 420 seconds

1 hour = 3600 seconds

Number of complete intervals:
3600 ÷ 420 = 8.57

Since the first strike is excluded, the number of complete strikes is 8.

Explanation

Formula: Area = r × s

Semi-perimeter: s = Perimeter ÷ 2 = 8 ÷ 2 = 4 cm

Therefore: r = Area ÷ s = 72 ÷ 4

= 18 cm