Answer:

The height of the portion AB of the lamppost is 14 tan(60°) or 14√3 feet.

Step-by-step explanation:

It is given that the tip of the lamppost touched the ground at point C, as shown below:

Triangle ABC has measure of angle C equal to 60 degrees, measure of angle ABC equal to 90 degrees, and length of BC equal to 14 feet.

Here, AB is perpendicular, BC is base and AC is hypotenuse.

In a right angled triangle,

tantheta=frac{perpendicular}{base}

tan(60^{circ})=frac{AB}{14}

14tan(60^{circ})=AB

14sqrt{3}=AB

Therefore the height of the portion AB of the lamppost is 14 tan(60°) or 14√3 feet.