At a certain time of day a person 6 ft casts a 4ft shadow. How long is the shadow cast by a 21ft tree at the same time?

Designate the unknown shadow length by s. Shadows cast at the same time and place are proportional to the height of the object casing the shadow. Therefore:

4/6 = s/21, or s = [4(21)]/6 = 14 feet.

answer: on graphs, the open and closed circles, or vertical asymptotes drawn as dashed lines us identify discontinuities.

as before, graphs and tables allow us to estimate at best.

when working with formulas, getting zero in the denominator indicates a point of discontinuity.

when working with piecewise-defined functions, check for discontinuities at the transition points where one piece ends and the next begins.

step-by-step explanation: