Answer: The answer is (A) 32 inches
Step-by-step explanation: Please refer to the attached diagram.
Since we have been given two sides of the television screen, that is, the length and the width, we can calculate the diagonal by simply drawing a line across from one edge to the other edge such that we now have a length, a width, and a diagonal. Simply put, we now have a right angled triangle with two sides given and the third side (the hypotenuse) yet unknown.
At this point we can apply the Pythagoras Theorem in solving for the unknown side. The Pythagoras theorem states that the square of the longest side in a right angled triangle equals the sum of the square of the other two sides of the triangle. This can be expressed as
AC^2 = AB^2 + BC^2
(Please note that ^2 means raised to power 2)
Where AC is the hypotenuse.
Our hypotenuse is represented by X in the attached diagram, hence
X^2 = 15.7^2 + 28^2
X^2 = 246.49 + 784
X^2 = 1030.49
Add the square root sign to both sides of the equation and we now have
X = 32.10
Approximate this to the nearest inch,
X = 32
The TV size is therefore 32 inches