Use words or pictures to explain how to measure an index card using color tiles

The easiest approach to measure an index card using color tiles is to first measure and label a color tile with a ruler. Because the question does not specify if this is allowed we must assume that it is. An index card is flat so there is no practical way to measure the thickness of it using a color tile. Therefore we can only measure either the width, height, or area of the card. To measure the width or height we simply align the edges of the card with the starting edge of the measured tile and use it as a ruler, moving it across the card until it overlaps the card's edge (if necessary.) To measure the area, we must measure the area we simply multiply the length times the width.