Angle BAE is part of a regular 18-sided polygon - OCR - GCSE Maths - Question 7 - 2017 - Paper 1

Using the same formula:

ext{Interior Angle}_{10} = rac{(10 - 2) imes 180}{10} = rac{8 imes 180}{10} = 144^{\circ}

Again, angle CAD is formed by the line of symmetry, so:

ext{Angle CAD} = rac{144^{\circ}}{2} = 72^{\circ}

Now to find angle BAC, we utilize the relationship:

$ext{Angle BAC} = ext{Angle BAE} + ext{Angle CAD}$

Substituting the values:

$ext{Angle BAC} = 80^{\circ} + 72^{\circ} = 152^{\circ}$

Therefore, angle BAC is:

$\boxed{152^{\circ}}$