Answer: 3 ways.
Explanation:
Given: Leigh will use 16 connecting cubes to make a model of playground.
To form rectangle write the above number of cubes in
form, where m represents the number of cubes in row and n represents the number of cubes column.
We now that by using prime factorization the number 16 can be written as

Thus, the cubes can be arranged as
or vice- versa such that the model will be in the shape of rectangle and will have the height of one cube.
Hence, in 3 different ways she can make the model of the playground.