Trigonometry can be used to find the area of a triangle when you know the length of two sides and the included angle.

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To be able to calculate the area of a triangle, you need to know two sides and the included angle.

\[Area = \frac{1}{2} ab \sin C\]

Find the area of triangle ABC.

\[Area = \frac{1}{2} \times bc \times \sin A\]

\[Area = 0.5 \times 3 \times 7 \times \sin (35^\circ )\]

\[Area = 6.02255...\]

\[Area = 6.02c{m^2}(to\,2\,d.p.)\]