Subject: ratios and area

Here is my question. The aspect ratio of this rectangle is 4:3. That is A to B is 3. And B to C is 4. If I know the lenght of A to C is 19 inches, how can I find the length of A to B, and B to C.

I'm not a student anymore.(way to old). But this problemÊhas been driving my crazy. I want to know the formula, so I can figure out the height and lenght of the viewing area, on all these new TVs. Sure hope you can help.

Ron Delavigne

Since the aspect ratio is 4:3 the rectangle is 4p inches by 3p inches for some number p.

By Pythagoras' theorem (4p)² + (3p)² = 19². That is 16 p² + 9 p² = 19². Hence 25 p² = 19² and thus p = 19/5 and thus the rectangle is 3x19/5 inches by 4x19/5 inches.