180=2x+y
180-y=2x
(180-y)/2=x
A circular pool with a diameter of 18 ft will have a uniform
4 ft concrete walkway poured around it. If the concrete cost $4.25 a square
foot, how much will it cost for the concrete?
This can be solve be solving the area of walkway
Area of walkway is equal to = (pi)( 9 ft +4) ^2– (pi)(9ft)^2
= 276.46 sq ft
Cost = 276.46 sq ft * ($4.25 a square foot) = $1174.70
Answer:
Step 4 is incorrect he did not divide correctly from step3 to step 4
Step-by-step explanation:
The circumference of a circle is
C = 2 * pi *r
We know the circumference is 12 pi
12pi = 2 pi *r
Divide each side by 2 pi
12 pi/2pi = 2pi r/ 2pi
6 = r
From step 3 The student did not cancel the pi in the top and the bottom on the right hand side to isolate r
In step 4 he got 6 =pi r instead of pi
2, No solution
3, Infinite many solutions
4, (0,-3)
i hope i was able to help!! so sorry if i made a mistake
