There are 21 groups of 3 in a room. how many people are there. i need an equation

Arandom number generator is used to model the patterns of animals in the wild this type of study is called

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

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax