Simplify:

Find a formula for sin A in terms of b and c only. (Note: △ABC is an isosceles triangle.)
Suppose that each of the following statements is true:
Which of the following conclusions must also be true?
On the assumption the following nine statements are factually correct, what conclusion, if any, can be drawn?
In a can of tennis balls that is exactly three balls high, which is greater, the volume of the balls or the volume of the air around the balls? (Disregard the thickness of the balls.)
A rectangular parallelepiped has edges with integral lengths x, y, and z. The sum of the lengths of all twelve edges is 72 inches. The sum of the areas of all 6 faces is 212 square inches. The volume of the solid is 144 cubic inches. Find the length in inches of a diagonal of this solid.
Express the area of this figure in simplest radical form. There are two right angles, and four other angles that are marked as being congruent.
An equilateral triangle and a regular hexagon have perimeters of the same length. If the triangle’s area is 2 square units, what is the area of the hexagon? Unless you’re a budding John Von Neuman, it isn’t necessary to calculate areas and then divide. That’s the hard way.
In parallelogram ABCD, M and N are midpoints of sides AD and BC, respectively. DN intersects AB at P, CM intersects AB at Q, and DN intersects CM at O. If the area of parallelogram ABCD is 24 square cm, find the area of triangle QPO.
In a rectangular coordinate plane, any circle that passes through (-2, -3) and
(2, 5) cannot also pass through (1989, y). Find the value of y.