What is the circumference of a circle with a radius of 2.5 feet

 The circumference of the circle is:  " 16 ft. " ;  
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or;  " In term of , the circumference of the circle is:  " 5  ft. " .
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Explanation:
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The formula for the circumference, "C" , of a circle:

→  " C = 2 * * r " ; 

→  in which:

      " C = circumference of the circle" ; 

       "r = radius ["length of radius"] = " 2.5 ft " (given) ; 

        = "3.14" ; which we can use as a commonly accepted 
                                              "approximated value" for "" ; 

                             =  " " ; or, we leave the symbol for "pi" as it is written; if 
                                                              we are to solve "in terms of pi" ; 
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Method 1)  To find the circumference, "C", of the circle; in term of "" :

Note the formula for the circumference, "C", of a circle:

C = 2 *  * r ; 

Plug in our given value for the "radius, "r" ; (which is: "2.5 ft.

→  C  =  2 *  * (2.5 ft) ; 

          =  2 * (2.5 ft) *  ;

          =   5    ft.
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 In terms of "" , the circumference of the circle is:  

                " 5   ft. "
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Method 2)  Solve for the circumference of the circle;
 
→ using "3.14" as an approximation for "" :
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Method 2)  [A]: 

→  Start by solving for the circumference; "in terms of " ;
              →  {as done above} :

Take the answer, which is:  " 5   ft" ;  

And solve using "3.14" as an approximation for "" :

→  " 5 * "  =  " 5 * (3.14) = 15.7 ft. ;

→  We can round to:  " 16 ft ." ← 2 significant figures.
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Method 2)  [B]:  To solve for the circumference of the circle;  
                    →  using "3.14" as an approximation for "" :

Note the formula for the circumference, "C", of a circle:

C = 2 *  * r ; 

Plug in our given value for the "radius, "r" ; (which is: "2.5 ft.") ; 

And substitute "3.14" as an "approximation for " ;
                                                                   →  in place of the for "" symbol ;

And rewrite: 
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→  C  =  2 * 3.14 * (2.5 ft) ; 

↔  C  =  2 * (2.5 ft)  * (3.14) ;

           =  (5 ft) * (3.14) ;

           =  15.7 ft. ; we can round to:  " 16 ft."  (2 signifcant figures).

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Plug in the value of radius = 2.5 into the formula:

Circumference  = 2π(2.5) = 15.71 ft (nearest hundredth)

15.71 ft

I’d say letter a..

I'll do the first one for you. it isn't very hard at all.on number one, you have (50 × 3), which equals 150, and (3 × 3), which equals 9. after you establish that, you add 150 and 9 together. so, (150 + 9) equals 159.this means that 53 × 3 = 159.