You can see it's an acute angle, so it's less than 90°. Image caption, Find the base line on the protractor (it's marked 0° at one end and 180° at the other end). Place the middle of the base ...

one pointing one way on the line, the other pointing the other way. Choose one, then take the “dot product” of each pair of vectors. If the vectors form an acute angle, the dot product will be ...

You can see it's an acute angle, so it's less than 90°. Image caption, Find the base line on the protractor (it's marked 0° at one end and 180° at the other end). Place the middle of the base ...