3/4y+6=0 steps in order

In the diagram, the measure of angle 9 is 85° which angle must also measure 85°?

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Enter the missing numbers in the boxes to complete the table of equivalent ratios of lengths to widths. ? 18 8 ? 10 30 12 ?