Answer:
56 inches
Explanation:
The aspect ratio of a TV in elementary terms is width/height expressed as a ratio. A 4:3 aspect ratio means that the width:height is 4:3
The size of a TV is the diagonal measure of the TV
For the given TV we are given that the size is 70 inches. This means the diagonal is 70 inches in length
If we let W = width and H = height of TV
Aspect ratio 4:3 means W/H = 4/3
H = 3W/4 (height:width = 3:4)
The diagonal D can be calculated from the width and length of the TV using the Pythagorean theorem
D² = W² + H²
Substitute H = 3W/4
D² = W² + (3W/4)²
D² = W² + 9W²/16
D² = (16W² + 9W²)/16
D² = 25W²/16
D = √(25W²/16) = 5W/4
W= 4D/5
Given D = 70 inches
W = (4 x 70)/5
W = 280/5
W = 56 inches