Answer:
828
Explanation:
Missing leg of triangle:
√15²-12²= √225-144=√81=9
Triangle faces= 2*1/2*12*9= 108
Base= 20*9= 180
Front face= 20*15= 300
Back face= 20*12= 240
Total= 108+180+300+240= 828
Second choice
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