Answer:
![44.16\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6nqpy2un6e003vo27udvbhif47aj38xv24.png)
Explanation:
I assume that there are 3 tennis balls inside the can
step 1
Find the volume of each tennis ball
we know that
The volume of the sphere (tennis ball) is equal to
![V=(4)/(3)\pi r^(3)](https://img.qammunity.org/2020/formulas/mathematics/high-school/904v6t92j764tuemw89ou00p3u81fhmqpa.png)
we have
![r=1.5\ in](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yfcuvnf4npqy89qkuxnbudv0vu1heou9q7.png)
substitute
![V=(4)/(3)\pi (1.5)^(3)=4.5 \pi\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8fimi2cou04ogy8n20yfca5veaew4e9uwd.png)
therefore
The volume of three tennis balls is equal to
![(3)4.5 \pi=13.5 \pi\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/983zar6ekr66uhijlfnf15kqu4f8oidf9i.png)
step 2
Find the volume of the can
The volume of the cylinder (can) is equal to
![V=\pi r^(2) h](https://img.qammunity.org/2020/formulas/mathematics/high-school/73kckbf8njaozpgvi2dq3iydzuyno3du3l.png)
we have
![r=1.75\ in](https://img.qammunity.org/2020/formulas/mathematics/middle-school/j0gfvp8aqschnpz8067ou1bqxq365tmp8e.png)
![h=9\ in](https://img.qammunity.org/2020/formulas/mathematics/high-school/y1jx60r3jm4mskd99jy696wgjoc1tmzmzd.png)
substitute the values
![V=\pi (1.75)^(2) (9)=27.5625 \pi\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xfstdvbcbs05ipyiosqgnwn8egeo5vsswn.png)
step 3
To find the empty space inside the can subtract the volume of the three tennis ball from the volume of the can
so
![27.5625 \pi\ in^(3)-13.5 \pi\ in^(3)=14.0625 \pi\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/b8l5qa4aqh2e97gggp009fg87o4me2vd2e.png)
use
![\pi=3.14](https://img.qammunity.org/2020/formulas/mathematics/middle-school/elnllul6m5wik5ibdc7x3b8auxqsmgjtbn.png)
![14.0625(3.14)=44.16\ in^(3)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7nq3j8itu1t3pl0w6rv5ftax9o28aupm1f.png)