We will find the perimeter as follows:
*First, we will determine the length of segment RT, that is:
[tex]\frac{RT}{6}=\frac{7.5}{4.5}_{}\Rightarrow RT=\frac{7.5\cdot6}{4.5}[/tex][tex]\Rightarrow RT=10[/tex]
*Second: We add the lengths of the sides of triangle RST:
[tex]P=5+7.5+10\Rightarrow P=22.5[/tex]
So, the perimeter of triangle RST is 22.5 units.
