Arthur D. answered 07/26/18
Tutor
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(267)
Forty Year Educator: Classroom, Summer School, Substitute, Tutor
draw a vertical line representing the pole
draw a diagonal line slanted upwards to the right; this is the string whose length you want
draw a horizontal line to the right from the top of the pole
draw a horizontal line to the right from where the kite is attached to the striing
these two horizontal lines are parallel
draw a vertical line downwards to the ground from where the kite is attached to the string
this vertical line is 45 feet
the distance of this vertical line, when it cuts the bottom horizontal line, is 40 feet and the rest of the line is 5 feet, the same height as the 5 foot pole
the angle of elevation of the string at the top of the pole is also 45º because the two horizontal lines are parallel
you now have a right triangle with the string as the hypotenuse, the 40 foot vertical line as one leg and the horizontal distance from the top of the pole to the vertical line drawn downwards from where the kite attaches to the string
use the sine function
sin45º=40/x where x is the hypotenuse and thus the length of string needed
x=40/sin45º
x=40/0.70710678
x=56.56854259 feet, rounded to 56.6 feet because the answer is an approximation due to the value of sin45º, which is how long the string must be in order for the kite to be 45 feet above the ground
you could round up anywhere, for instance, 56.569 feet would be long enough