When the radius of a circle is decreasing

MATHEMATICS · Single correct · AP · Calculus AB · Contextual Applications of Differentiation · Contextual Applications of Differentiation

Problem

When the radius of a circle is decreasing, which statement about

\dfrac{dA}{dt}

is necessarily true? (a)

\dfrac{dA}{dt}

is positive (b)

\dfrac{dA}{dt}

is zero (c)

\dfrac{dA}{dt}

is negative (d) Sign of

\dfrac{dA}{dt}

cannot be determined from the given information