Use the scale tool for scaling the FW shapes. The scale tool also combines with the Fireworks' skew and distort tool, both of the tools can also be used to modify the selected vector graphic. The shape can also be flipped vertically or horizontally. The center of the scaling can be re-positioned. Personally, I find the scaling of Fireworks symbols and paths a little more fiddly than the basic transform panel in many of the other Adobe Creative Cloud applications.
You can also scale the symbols by double clicking the Fireworks symbols and then using the pointer tool to increase the size of the work (or decrease). You then need to exit from editing the symbol.
Modify menu and transform command and scale. The same as the scale tool. There are other transformations such as skew and distort and flip. One interesting option is the numeric transform for scaling of FW shapes as this does at least offer options for scaling attributes and proportions as well as resize and rotate. The resize is basically the same as scaling but it just sets the size as required and requires no mathematical calculation.
The FW symbols can be scaled via the properties panel as you can change the W (width) and H (height) of the symbol - the equivalent of scaling a symbol.