Use the drawing tool bar - shapes select circle - lines - bisect circle with as many lines as you need to create the correct number of segments, use the colour select and fill tool to fill the segments with the correct colours.
Using Word97 got to View/Toolbars and selct 'Drawing' this should give you a drawing toolbar at the bottom of the screen. Go to the draw button (left hand side) select 'Grid' and uncheck 'Snap to grid. Now Autoshapes/Basic Shapes and select the isosceles triangle,draw a triangle. Right click on triangle and select 'Format Auto Shape and in the window that opens 'Fill Color/More Coplors/Custom and choose a colour. Then copy and paste this triangle, fill with a different colour, click on the 'Free rotate' button at the bottom of tjhe screen (second from left), rotate and move to join with other shape. Repeat until you have a circle.