3x(8r-1) x (4r+2s)
3x7r x (4r+2s)
21r x (4r+2s)
35 cm
using the formula a=1/2(b)(h), we can plug in 14 for b and 5 for h. This gives us 70, and when we multiply by 1/2 it leaves 35 cm.
Another user previously answered this same question and had a good rating, his answer was as follows:
"{-9; -6.5; -5.2}"
Which I suppose would be answer D.
- Hope it helps.
