(i)[6]
Find angle $ABC$ by using a scalar product.
(ii)[2]
Calculate the perimeter of triangle $ABC$, with your answer correct to $2$ decimal places.
Mathematics 9709 · AS & A Level · Coordinate geometry
Coordinate geometry — practice question
With respect to an origin $O$, the position vectors of points $A$, $B$ and $C$ are $overrightarrow{OA} = \mathbf{i} - 2\mathbf{j} + 4\mathbf{k}$, $\overrightarrow{OB} = 3\mathbf{i} + 2\mathbf{j} + 8\mathbf{k}$, and $\overrightarrow{OC} = -\mathbf{i} - 2\mathbf{j} + 10\mathbf{k}$.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Right vectors $\pm(2\mathbf{i}+4\mathbf{j}+4\mathbf{k})$ or $\pm(4\mathbf{i}+4\mathbf{j}-2\mathbf{k})$.” …
- Full mark scheme, point by point
- Step-by-step worked solution
- Write your answer & get it marked instantly by AI