Answer:
Use the Pythagorean Theorem to calculate the length of the sides of a right triangle. A TV cut in half on the diagonal is a right triangle.
a^2 + b^2 = c^2
a is the width of the TV
b is the height of the TV
c is the diagonal size of the TV
a is equal to the length of b plus 15, and c is equal to 75. If we out those values into the formula, we get this:
(b+15)^2 + (b)^2 = (75)^2
Factoring that out, we get:
(b)^2 + 225 + (b)^2 = 5625
Then..
2b^2 = 5625 - 225
2b^2 = 5400
b^2 = 5400/2
b^2 = 2700
b = ✓2700
b = 51.9615242271 (round it to an even 52)
Next, we know that a = b + 15, so a = 67.
Therefore, the width of the TV is 67 inches, the height is 52 inches, the diagonal is 75 inches, and you have a very strangely shaped television with a 1.288 (approximately 5:4) aspect ratio. Older “square” TVs mostly had a 1.33 (4:3) ratio, and new TVs are usually either 16:9 (1.77) or 21:9 (2.33). While it's not impossible that you have an old square TV with a 75 inch diagonal, it's pretty unlikely…
Explanation: