General formula for circles at the origin is x^2+y^2=R^2 where R is the radius.So R^2=4225. Solve for R.
Add sin(x) to both sides
tan(x)sin(x)=sin(x)
Divide sin(x) from both sides
tan(x)=1
now you just have to figure out where tan(x)=1. you can figure this out from there by looking at the unit circle.
1/2 x > 0.4x
where Robert's spending is greater than Rosa's spending.
Allowance of Rosa = Allowance of Robert
let x = allowance
Rosa : video games = 0.4(x) ; pizza = 2/5 (x)
Robert : video games = 1/2 (x) ; pizza = 0.25 (x)
let us assume that their allowance is 100 each week. so, x = 100
Rosa : video games = 0.40(100) = 40
pizza 2/5 (100) = 200/5 = 40
total spending: 40 + 40 = 80
Robert : video games = 1/2 (100) = 50
pizza 0.25 (100) = 25
total spending: 50 + 25 = 75
Spending on video games
Rosa = 40
Robert = 50
Robert spent more of his allowance on video games than Rosa.
1/2 x > 0.4x
