what is the surface area of the monument

Answer:
660
Step-by-step explanation:
ok this one is a little more tricky
20*5=100 do not double this one
20*12=240 do not double this one
20*13=260 do not double this one
remember the area of a triangle is A=1/2l*w
plug in the values
A=1/2(5)(12)
A=30 you have to double this one because there is two of them
60
now you must add up all your values
100+240+260+60=660
i hope i am not wrong... but hope it helps!