Answer:
the amount of space a 3-dimensional object takes up
Step-by-step explanation:
Of the four definition options, the first is the only only that incorporates a three dimension explanation.  The others only describe a two dimension object.  Units for the first would be unit^3.  The other three would only be one-dimensional "units."
 
        
             
        
        
        
let's recall the vertical line test, it's a function if when dropping a vertical line on the graph, it only touches it once on the way down.
Check the picture below.
 
        
             
        
        
        
Answer:
d
Step-by-step explanation:
 
        
                    
             
        
        
        
Area is trapezium = 
A=1/2h(a+b)
84=1/2(6)(7+b)
84=3(7+b)
84=21+3b
3b=84-21
B=63/3
B= 21 cm
I’m sorry if my answer turned out to be wrong but I tried my best so best of luck !!