3.93: Triangle with given angles (no calculator)

0606/23/O/N/23 — Question 7 · 7 marks

Do not use a calculator in this question.

3.93 diagram3.93 diagram
In triangle ABCABC, angle A=60A=60^{\circ}, angle B=75B=75^{\circ}, angle C=45C=45^{\circ} and AB=2AB=\sqrt{2}.
You may use sin60=32\mathrm{sin}\,60^{\circ}=\dfrac{\sqrt{3}}{2}, sin45=22\mathrm{sin}\,45^{\circ}=\dfrac{\sqrt{2}}{2}, cos60=12\mathrm{cos}\,60^{\circ}=\dfrac{1}{2}, cos45=22\mathrm{cos}\,45^{\circ}=\dfrac{\sqrt{2}}{2}, tan60=3\mathrm{tan}\,60^{\circ}=\sqrt{3}, tan45=1\mathrm{tan}\,45^{\circ}=1.
(a)
Given that the area of triangle ABCABC is 3+34\dfrac{3+\sqrt{3}}{4}, show that sin75=6+24\mathrm{sin}\,75^{\circ}=\dfrac{\sqrt{6}+\sqrt{2}}{4}.
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(b)
Hence find the exact length of ACAC.
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