Respuesta :

mhanifa

Answer:

828

Step-by-step 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