The diagonal of andres rectangular tv screen is 39 in. the width of his tv screen is 34 inches. which measurement is closest to the height of andres tv screen?

choice B) 19.1 inches



Explanation:

The TV is a rectangle. Cut the rectangle into two triangles along the diagonal of the rectangle. Focus on only one of the triangles. This triangle is a right triangle.

Since we have a right triangle, we can use the pythagorean theorem
a = 34 is the width
b = x is the unknown height
c = 39 is the diagonal
'a' and 'b' are the legs of the right triangle
c is the hypotenuse

Plug those values into the pythagorean theorem to solve for x
a^2+b^2 = c^2
34^2+x^2 = 39^2
1156+x^2 = 1521
1156+x^2-1156 = 1521-1156
x^2 = 365
sqrt(x^2) = sqrt(365)
x = sqrt(365)
x = 19.1049731745428
which rounds to 19.1