7. Non-Right Triangles

Which of the following formulas could be used to calculate the area of a sector in a circle with radius $r$ and central angle $\theta$ (in radians)?

Which triangle's area can be calculated using the trigonometric area formula $A=\frac{1}{2}absinC$?

Which of the following formulas correctly gives the perimeter of a parallelogram with side lengths $a$ and $b$?