Marisol buys 3 notebooks that each cost the same amount and 1 calculator that costs $9. The total cost is $21. How much does each notebook cost?

Step-by-step explanation:

4 dollars for each notebook

Step-by-step explanation:

21-9= 12

12/3=4

each notebooks costs 4 dollars

true

step-by-step explanation:

2.2°  

step-by-step explanation:

let θ = the angle of elevation.

tanθ =77/2020

tanθ = 0.038 12

      θ = tan⁻¹0.038 12

      θ = 2.2°