Given position vectors a = 4i − 3j, b = 2i + 4j, c = 14i + 6j, find angle ABC, correct to the nearest whole number.

Here are the solutions to problems 14 and 15.

: Vectors

Given position vectors:
$\mathbf{a} = 4\mathbf{i} - 3\mathbf{j}$
$\mathbf{b} = 2\mathbf{i} + 4\mathbf{j}$
$\mathbf{c} = 14\mathbf{i} + 6\mathbf{j}$

a) Find angle ABC, correct to the nearest whole number.

Step 1: Find the vectors $\vec{BA}$ and $\vec{BC}$.

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