Answer:
Length of mammoth's tusk in poster = 15.33
Explanation:
Actual height of mammoth = 10 feet 5 inches = 126 inches
Height on the poster of mammoth = 14 inches
Actual length of mammoth's tusk = 11.5 feet = 138 inches
Length of mammoth's tusk in poster = x
126 : 14 :: 138 : x
Product of mean = product of extremes
x * 126 = 14 * 138

x = 15.33