Imagine a right triangle where a and b are the legs and c is the hypothenuse.
Pitagora: a²+b²=c²
Divide by c
(a/c)²+(b/c)²=1
But a/c=sin(B) and b/c=cos(B)
Thus sin² + cos² = 1
$5. Subtract the cost of the magazine, $3, from the total cost, $28. Now you have $25 then you divide it by the amount of notebooks you have.
Should be the 2nd and 3rd one
