Need good answers for this geometry class plz What can you tell about a triangle when given three side lengths?

What can you tell about the relationship between the angles of a triangle and its sides?

The amount of money, in dollars, in an account after t years is given by a = 1000(1.03)^t. the initial deposit into the account was $_^a0 and the interest rate was _a1% per year. only enter numbers in the boxes. do not include any commas or decimal points^t. the initial deposit into the account was $__^a0 and the interest rate is % per year.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Can you me find the missing length. i attached an image.