You need to use SOHCAHTOA. Sin (opposite/hypotenuse) Cos (adjacent/hypotenuse) Tan (opposite/adjacent)
For the first photo, you would use Tan( opposite/adjacent) 4/x = tan(20) Then you just change the equation to have x on the side by itself. (4)(tan20) = x Then write that into the calculator.
For the second problem, you use Sin(opposite/hypotenuse) Sin(25)=x/10 Change the equation to have x by itself. Sin(25)(10)=x Then plug it into the calculator.
You have to add/multiply 2.50 by 3 to get the total cost of the cards. 2.50*3=7.5. then, you need to add/multiply 3.00 by 2 to get 6. 7.5+6= 13.5. 20-13.5=6.50.