Answer:
22.5
Step-by-step explanation:
To find the rate of speed per hour, you need to divide the kilometer (90) by the hours (4).
90/4=
22.5
Answer:
Perimeter of Triangle: 

Step-by-step explanation:
The perimeter is the sum of all of the sides of the triangle.
Hence, the perimeter 
Since the perimeter is 90,
.
Subtract 15 from both sides:


Divide both sides by 6:

