The sum of all interior angles in a polygon is
180(n-2), where n = sides, well, this is a QUADrilateral, so it has 4 sides, so the total is 360°.
now, let's find what angle C is first,

now, recall the "inscribed quadrilateral conjecture", where opposite angles are "supplementary angles", thus
Answer:
Tip: 4,2
Total cost: 32,2
Step-by-step explanation:
Tip: (28×15)÷100 = 4,2
Total cost: Tip + original money
--> 4,2 + 28 = 32,2
3.528571429
Hope This Helps!!