amount of material =area
area of triangle=1/2 times base tiems ehighte
base=2 and 1/4
height=8 and 1/2
convert all to imporpoert
2 and 1/4=2+1/4=8/4+1/4=9/4
8 and 1/2=8+1/2=16/2+1/2=17/2
so we have
area=1/2 times 9/4 times 17/2
area=(1 times 9 times 17)/(2 times 4 times 2)
area=153/16
area=9 and 9/16
answer is 9 and 9/16 square units of material