Add the ratios 3:1 = 4
divide perimeter 128 by 4 = 32
multiply this by each ratio so 3:1 becomes 96length:32width
remember there are two lengths and two widths in the perimeter so divide by 2 to find the length = 48
What figures are you talking about, can you post the picture?
divide the frequency of 6 by the total frequency to obtain a probability
(also 15%)