help!!!!!

To multiply to numbers in  r·cis(theta) form, multiply the r-values, and add the angles.

 

The formula is:  r₁·cis(A₁) x r₂·cis(A₂)  =  r₁·r₂·cis(A₁ + A₂)

 

10(cos30^o + i sin30^o)  can be written as  10·cis(30^o)

5(cos10^o + i sin10^o)  can be written as  5·cis(10^o)

 

Can you use the formula to get your answer?