Question

david study table is 20 inches long. if the diagonal measures 25 inches, find the width of david study table

Answer 1

15

Explanation:

You can use Pythagorean theorem or if you draw it out and label the given information you may recognize that the triangle created is a 3 - 4 - 5 triangle.

`25^(2)` =
`20^(2)` +
`x^(2)`
`c^(2)` =
`a^(2)` +
`b^(2)`

625 = 400 +
`x^(2)`

225 =
`x^(2)` Square root both sides

15 = x

A special right triangle has a leg that measures 3, another leg that measures 4. and a hypotenuse that measures 5.

The given triangle in this problem has a leg that measures 20 and a hypotenuse that measures 25. If you divide each measure by 5, you will have a leg that is 4, and a hypotenuse that is 5. That means the last leg must be 15.

Why? Because 3 x 5 = 15. or 15/5 = 3

This comes up very often when working with triangles.

Answer 2

15 inches

Explanation:

Since we know diagonal and a side of a right triangle, we can use the Pythagorean theorem to solve.

a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse

20 ^2 + b^2 = 25^2

400+b^2 =625

b^2 =625 -400

b^2 =225

Taking the square root of each side

sqrt(b^2) = sqrt(225)

b= 15