Question

While standing in line for the water fountain, Brian sees his lab partner 4 feet ahead of him and his best friend 7 feet to his right. Brian wants to go ask his lab partner a question, then go chat with his friend, and finally return to the water fountain line. How far will Brian have to walk in all? If necessary, round to the nearest tenth.

Answer 1

Look at the Fig.1

A – the point, where Brin is standing (the water fountain line)

B - the point, where his lab partner is standing (4 feet)

C - the point, where his friend is standing (7 feet)

ΔABC – right angled triangles

Brain’s way:

1.     to go ask his lab partner a question:

from point A to B = 4 (feet)

2.     to go chat with his friend:

from point B to C

Use Pythagorean theorem:

$\boxed{a^2+b^2=c^2}$ , where

a=AB=4; b=AC=7;

c=BC=?

c=$\sqrt{a^2+b^2}=\sqrt{4^2+7^2}=\sqrt{65}\approx$ 8.06 (feet)

3.     return to the water fountain line

from point C to A = 7 (feet)

4.    Sum all route segments:

4+8.06+7 $\approx$ 19.1 (feet)

Answer: 19.1 feet