standard_description: Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.
problem_activity: Explain why
$${\frac{1}{2}ab\mathrm{sin}(C)}$$
gives the area of a triangle with sides
$$a$$
and
$$b$$
and included angle
$$C$$
.


aligns: no