1.) what is the difference in weight of two boxes of cereal, one weighing 1 pound 4 ounces and the other weighing 13 ounces? 2.) if you divide a 6-foot-8-inch board into four equal lengths, how long will each piece be?

You first need to know your conversions:

1 pound = 16 ounces,  1 foot = 12 inches

1.  so 1 pound 4 ounces = 20 ounces. Now subtract that with 13 and you should get 7 ounces

2. so 6 foot by 8 inch board =  80 inches. Now divide that with 4 and you should get 20 inches

hope that helps :)

the arc length is found by finding the circumference of the full circle (2xpixradius) and then dividing by 4 to find just one quarter of the circle (90 degrees).