Answer
Diagonal Distance from the plane to the runway = 1.3 miles
Work Step by Step
Given approach of the airplane forms a right triangle (as in given figure 22) in which length of diagonal will be the required distance-
Given-
Horizontal distance = 1.2 miles
Altitude of the plane = 2640 feet = $\frac{2640}{5280}$ miles
( Given, 1 mile = 5280 feet)
Altitude of the plane = $\frac{1}{2}$ = 0.5 miles
Using Pythagorean theorem-
$Diagonal Distance^{2}$ = $Horizontal Distance^{2}$ + $Altitude^{2}$
$Diagonal Distance^{2}$ = $(1.2)^{2}$ + $(0.5)^{2}$
= 1.44 + 0.25 = 1.69
Therefore Diagonal Distance = $\sqrt (1.69)$ = 1.3 miles
