This does not appear to be a right triangle. However, we know 2 sides and the included angle, so can find the unknown side length. Let x represent this length. Then:
x^2 = 81 + 144 - 216(sqrt(3) / 2). Please solve for x^2 and then solve the result for x, making sure to choose the positive value. The result will be the length of the side opposite the 30 degree angle.
With 1 of 3 angles known, and 3 of 3 sides known, you can use the Law of Sines to find the other two angles. As a reminder, the Law of Sines looks like this:
a b c -------- = --------- = ---------- sin A sin B sin C.
You can give the 30-deg angle any name you want; then a, the length of the side opposite the 30-deg angle, which you have just found. And so on.
The answers are <span>I. Two pairs of opposite angles congruent. II. A pair of adjacent angles are supplementary. </span> <span>VIII. The diagonals bisect each other. </span>
For this case we have the following equation: Where, w: The weight of a spring in pounds E: the energy stored by the spring in joules. Substituting values we have: Making the corresponding calculation: Answer: the approximate weight of the spring in pounds is: