A rock is tossed into a lake and creates a ripple with a radius that increases at a rate of 20 cm/sec. The radius of the ripple can be expressed as the function R(t) = 20t, where t represents time in seconds. The area of the circle made by ripple can be expressed as the
function () = qır?, where r represents the radius in centimeters.

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?

Line ab is y = -7/5x + 56/5i don't understand  where point d comes into this.