Estimate 543-358 then find the difference

The hawaiian alphabet has 12 letters. how many permutations are posible for each number of letters?

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn. if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.

Geometry in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.