find the perimeter of a rectangle if the width is 4 feet and the length is 3 times as long as the width

4x3 = 12 ft (length)
2(4+12)
32ft

To solve this problem you must apply the proccedure shown below:

 1- You have the following information given in the problem above:

 - The moon forms a right triangle with the Earth and the Sun during one of its phases.

 - The angle between the line joining the Earth and the moon and the Sun and the moon is x degrees.

 - The distance between the Earth and the Sun is y.

 2- Therefore, you have:

 d: distance between the moon and the sun

 Sin(α)=opposite/hypotenuse

 α=x
 opposite=y
 hypotenuse=d

 3- Therefore, you have:

 Sin(x)=y/d
 d=ySin(x)

 The answer is: The scientist can calculate the distance between the moon and the sun, by applying the trigonometric identity: Sinα=opposite/hypotenuse, where the opposite side is the distance between the earth and the sun (y), α is the acute angle between the line joining the Earth and the moon and the Sun and the moon (x degrees) and the hypotenuse is the distance that they need to calculate (d). Therefore, the need to solve for d.