Krishnan had $10.he bought box of crayons and a pen. A box of crayons cost twice as much as a pen. He received $4 change. how much did the pen cost?

Jim makes $10.35 per hour. write an equation that jim can use to calculate his pay.

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?