Percent of Change

               The Three Main Topics: percent of change

                                                                            greatest possible error

                                                                            percent error

Percent of Change: amount of change

                                              original amount

ex; The price of a sweater decreased from 29.99 to 24.99

Find percent of change.

            29.99-24.99=5.50= .183             18.3% decrease

                                 29.99

greatest possible error (GPE): 1/2 of measuring unit

ex A; a book is 8in long = 1/2 inch = .5in

     B; ................10.5cm = 1/2 (.1) = .05cm

     C; ................7.53in = 1/2 (.01) = .005in

ex; find the min. & max. error = 1/2 inch = .5in

                                         min: 6.5 x 12.5 = 81.25ft(2)

                                         max: 7.5 x 13.5 = 101.25(2)

Percent error:          GPE      

                                    measurement

ex; Diameter of a CD is measured to be 12.1 cm. find the percent error.

GPE = 1/2 (.1) = .05cm                    PE:   .05/12.1= .0041 = .41%

ex; Find the percent error in calculating volume.

                                                   min. dim. : 10.5 x 1.5 x6.5 = 102.375cm(3)

                                                   max. dim. : 11.5 x 2.5 x 7.5 = 215.625cm(3)

                                                   measured volume : 11 x 2 x 7 = 154cm(3)

                  The biggest difference occurs between the maximum volume and the measured volume, so use that as your GPE.

                               The PE =

                                                            =  40% error