Step-by-step explanation
Let's make a drawing of the situation of the exercise.
Oliver covered the 4 sides of the kite with 7200 cm^2 of ... If we define x:= Area of each side, we get
![4x=7200\operatorname{cm}^2\text{.}]()
Solving this equation for x, we get
![\begin{gathered} x=(7200)/(4)cm^2, \\ x=1800\operatorname{cm}^2\text{.} \end{gathered}]()
Now, let's recall the formula for the area (A) of a rectangle:

Let's choose any side of the kite and define h to be the height of the kite. Note that h is also the width of the chosen side. Besides, its width is given; it's 30 cm. Then, we get the equation
![1800cm^2=h\cdot(30\operatorname{cm})\text{.}]()
Solving this equation for h, we get
![h=\frac{1800\operatorname{cm}}{30\operatorname{cm}}=60\operatorname{cm}.]()
Hence, the height of the kite is 60 cm.
Now, the volume inside the kite (V) is given by

Applying this formula to our case, we get
![\begin{gathered} V=(30\operatorname{cm}\cdot30\operatorname{cm})\cdot(60\operatorname{cm}), \\ V=54000\operatorname{cm}^3\text{.} \end{gathered}]()
Answer
The volume inside the kite is
![54000\operatorname{cm}^3.]()