Find the approximate increase in the area of a circular disc if its diameter is increased from 44cm to 44.4cm

Answer 1

Since the exact increase can be calculated readily by
π(r2²-r1²)
=π(44.4²-44²)
=35.36π

I assume you are working on linearization in calculus.

Let
A(r)=πr²
A'(r)=2πr
Approximate increase in area
=A'(r)Δr
=2πr*Δr
=2π(44)(0.4)
=35.2π (approximately)