Explanation:
after mixing 1 can of concentrate and 3 cans of water, we will have 4 cans of juice.
the volume of 1 can is (as for any cylinder or regular 3D object)
base area × height
for a cylinder the bar area is the area of a circle
pi×r²
r is the radius, which is half of the diameter.
in the picture it is not fully clear what is 2.25 in long : the diameter of the radius ?
I suspect it is the diameter.
so, the radius of our cans is 2.25/2 = 1.125 in
the volume of 1 can is
pi×1.125²×4.25
and the volume of all 4 cans of juice is then
4×pi×1.125²×4.25 = 17×3.14×1.265625 = 67.5590625 in³
≈ 68 in³
so, your answer is 68.