Question

A circular metal plate expand under heating so that its radius is increased by 2% find the approximate value in the area of the plate if the radius of the plate before eating is 10 centre

Answer 1

Answer:

4.04 %  ≈ 4 %

Step-by-step explanation:

Initial Radius of plate = 10 cm

Area of plate = π (10)²   cm²

Increase in radius = 2 %

Increased Radius = 10 + (2/100)10  = 10.2 cm

Increased Area = π (10.2)² cm²

increase in Area = π (10.2)² - π (10)²  cm²

using a² - b² = (a + b)(a -b)

= π (20.2)(0.2)  cm²

= π (4.04) cm²

% increase in Radius = (π (4.04)/100π) * 100  = 4.04 %  ≈ 4 %

the approximate % increase in the area of the plate  = 4 %