The area of a rectangle is 9.312 x 104 cm2 and the width is 2.56 x 102 cm. what is the length? a) 3.6375 x 102 b) 3.6375 x 106 c) 6.752 x 102 d) 6.752 x 106

Area = length*width
length = Area/width
  = (9.312*10^4)/(2.56*10^2) = 3.6375*10^2 . . . cm

Selection A is appropriate.


You already knew that before you even touched your calculator. 10^4/10^2 = 10^2, so only answers A and C should be considered. 9.3/2.6 < 4.5, so only answer A should be considered.

The beauty of scientific notation for numbers is it helps you estimate the result of multiplication and division easily. For many problems, you don't need the actual answer as much as you need the ballpark in which the answer resides.

The unit price is 0.99

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.