Can anybody help me please, I'll give brainlest for correct answer​

Answer soon(fast) 15 pts-brainliest? for right answer with small explination a restaurant catered a party for 40 people. a child’s dinner (c) cost $11 and an adult’s dinner (a) cost $20. the total cost of the dinner was $728. how many children and adults were at the party? use the table to guess and check.(i couldn't get the graph onto the question)                                8 children and 32 adults9 children and 31 adults10 children and 30 adults12 children and 28 adults

Find the constant of variation for the relation and use it to write an equation for the statement. then solve the equation.

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?