what is the ratio of the length to the width
The length-to-width ratio is calculated by dividing the length of the marquise by the width. (Example) Oval length equals 6 millimeters; oval width equals 4 millimeters; 6 millimeters divided by 4 millimeters equals a length-to-width ratio of 1.5 to 1. Diamonds are rarely cut to a perfect 1.5 to 1 ratio.