Your supposed to use sin= op over hypotenuse, coh= adjacent over hypotenuse , and tan= opposite over adjacent
4. For this you would use tan b/c the angle is opposite the degree and you have no hypotenuse. Equation will be tan30/1 = radical 6/x. And solve
3. Would be using sin with the equation
Sin45/1 = 7 radical 6/2 over x
