Prove that if both pairs of opposite sides of a quadrilateral are equal, then the quadrilateral is a parallelogram

An airplane consumes fuel at a constant rate while flying through clear skies, and it consumes fuel at a rate of 64 gallons per minute while flying through rain clouds. let c represent the number of minutes the plane can fly through clear skies and r represent the number of minutes the plane can fly through rain clouds without consuming all of its fuel. 56c+64r < 900056c+64r< 9000 according to the inequality, at what rate does the airplane consume fuel while flying through clear skies, and how much fuel does it have before takeoff? the airplane consumes fuel at a rate of gallons per minute while flying through clear skies, and it has gallons of fuel before takeoff. does the airplane have enough fuel to fly for 60 minutes through clear skies and 90 minutes through rain clouds?

(05.02)how many triangles can be made if two sides are 4 inches and the angle between them is 90°? 1 , 2, more than 2, or none

Chase is working to earn money for a cd player. on saturday, he earned half as much as he did on sunday, but twice as much as he did on friday. during the 3 days, he earned $70.00. how much did he earn each day?