Use Vectors to Find the Measure of the Angle at Vertex

question 7

Multiple Choice

Use vectors to find the measure of the angle at vertex B of triangle ABC,when $A = ( 5,1 )$ , $B = ( - 5,1 )$ ,and $C = ( - 3 , - 5 )$ .Round answer to two decimal places.

• A)69.48°
• B)71.57°
• C)72.91°
• D)70.38°
• E)74.09°

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