1. The problem statement, all variables and given/known data Given the vectors: P = 8i +5j-Pzk m and Q = 3i -4j-2k m Determine the value of Pz so that the scalar product of the two vectors will be 60m2 2. Relevant equations Sure seems like we will need to use the following equation: P * Q = |P| * |Q| * cos ∅ But I don't recall being able to be taught the angle between two vectors so cos would still be unknown? 3. The attempt at a solution Also, I assume the scalar product being 60 means that PQ = 60, or that: Q = √32+-42+22 = √29 So, P would be 60/√29 Then this equation should be solved such as 60/√29 = √82+52+(-Pz)2 11.14172029 = √82+52+(-Pz)2 124.13793 = 89 + (-Pz)2 35.13793 = (-Pz)2 This would give an answer of about +/- 5.92, but in my solution manual I see that the solution is -28. Where have I gone wrong?