Heating sample too rapidly may cause the thermometer reading to differ from the actual temperature of the heat source. Why is a finely powdered sample used in a melting point measurement? Particles may not pack well.
P = 2w + 2l where w is the width, and l is the length. We know the length (l) is 3 inches longer than it's width (or l = w+3). Substitute w +3 into Perimeter equation. P = 2w + 2(w+3).
