If i have 4 right angles that means i have for perpendicular lines segments too right?

Tickets to a science exposition cost $5.75 each for studentd and $7.00 for adults.how many students and adults went if the ticket charge was $42.75

An engineer scale model shows a building that is 3 inches tall. if the scale is 1 inch = 600 feet, how tall is the actual building?

How many and of which kind of roots does the equation f(x)=2x^4−9x^3+17x^2−16x+6 have?