How many times does a dragonfly flaps it's wing in 1000 seconds

Determine which postulate or theorem can be used to prove that lmn =nmo

Ateacher wanted to buy a chair, a bookshelf, two tables and a desk. she spent $900 for all five items and the chair and the desk combined 70% of her total. if the bookshelf cost $50, how much did each of the tables cost?

Use the given information to determine the exact trigonometric value.