If you have a block of steel with a density of 7.8g/cm3 and a block of gold with a density of 19.3g/cm3 each with the same volume which would be heavier and why

The vector a? is 3.50 cm long and is directed into this page. vector b? points from the lower-right corner of this page to the upper-left corner of this page and has the components bx=-19.5 cm , by=25 cm. in the right-handed coordinate system, where the +x-axis directed to the right, the +y-axis toward the top of the page, and +z-axis out of the page, find the x-component of the vector product a? ×b? , measured in cm2.