Question 113645:  Determine the surface area and the volume for 5 blocks and 6 blocks.
 
Number of Blocks           Surface area (in square cm)        Volume (In cubic cm)                               
Block 1=			18cm area	                       	4 cm volume 
Block 2=			30 cm	area			8 cm  vol			 
Block 3=			42 cm	area			12 cm vol		 
Block 4=			54 cm	area			16 cm	vol	 
Block 5=  			66 cm	area			20 cm  vol 
Block 6=         			78 cm   area	       		24 cm  vol
 
 
Which I have done already.  I am now supposed to: write an algebraic expression to represent the relationship between the number of blocks and the surface area of the tower.  
and use mathematics to justify my answer. What  I do know: the surface area with each block adds 12 more cm and with each block added the volume increases by 4 cm, so do the 12 and 4  need to be in the expression and how would I express it? 
 
 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! Determine the surface area and the volume for 5 blocks and 6 blocks.
 
Number of Blocks           Surface area (in square cm)        Volume (In cubic cm)                               
Block 1=			18cm area	                4 cm volume 
Block 2=			30 cm	area			8 cm  vol			 
Block 3=			42 cm	area			12 cm vol		 
Block 4=			54 cm	area			16 cm	vol	 
Block 5=  			66 cm	area			20 cm  vol 
Block 6=         		78 cm   area	       		24 cm  vol
 
 
Which I have done already.  I am now supposed to: write an algebraic expression to represent the relationship between the number of blocks and the surface area of the tower.  
and use mathematics to justify my answer. What  I do know: the surface area with each block adds 12 more cm and with each block added the volume increases by 4 cm, so do the 12 and 4  need to be in the expression and how would I express it?  
------- 
Let "x" be the number of blocks 
Surface area = 6 + 12x sq.cm. 
Volume       = 4x cu.cm 
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You did well to notice the pattern. 
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Cheers, 
Stan H.
 
 
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