Label the line PQ. Construct this line parallel to the bottom of the triangle. Remember, all of the angles that comprise a straight line must be equal to 180. Because angle PAB, angle BAC, and angle CAQ combine together to make line PQ, their angles must sum to 180. Call this Equation 1. Because you constructed line PQ parallel to side BC of the triangle, the alternate interior angles (PAB and ABC) made by the transversal line (line AB) are congruent. Similarly, the alternate interior angles (CAQ and ACB) made by the transversal line AC are also congruent. Equation 2: angle PAB = angle ABC Equation 3: angle CAQ = angle ACB It is a geometric theorem that alternate interior angles of parallel lines are congruent. Knowing that the alternate interior angles are equal lets you substitute the angles of the triangle for the angles of the line. Thus we get, Angle ABC + angle BAC + angle ACB = 180. In other words, in the triangle ABC, angle B + angle A + angle C = 180. Thus, the sum of all the angles of a triangle is 180.

Summary: Draw a line parallel to side BC of the triangle that passes through the vertex A. Write the equation angle PAB + angle BAC + angle CAQ = 180 degrees. State that angle PAB = angle ABC and angle CAQ = angle ACB. Substitute angle PAB and angle CAQ in Equation 1 for angle ABC and angle ACB (as found in Equation 2 and Equation 3) respectively.

Oysters should still be alive when you shuck them; if they've already expired, they aren't safe to eat. Pick oysters with the following properties: Closed shells. If an oyster's shell is open, it's likely that it's already dead. Lightly tap the shell, just in case; if it immediately shuts, the oyster is still alive and fine to eat. A fresh sea smell. Fresh oysters smell both sweet and salty, like the air next to the sea. If an oyster smells fishy or "off," it's probably not fresh. A heavy feel. Place the oyster in your palm. If has a nice heavy weight, that means it's still full of seawater and was probably harvested quite recently. If it's unexpectedly light, the seawater has dried up, and it's no longer fresh. Besides a nice sack of fresh oysters, you'll need the following supplies: A stiff-bristed brush Heavy gloves An oyster knife, or another knife with a heavy blade that won't snap A bed of ice for keeping the oysters fresh until serving Before you start shucking, take a close look at an oyster so that you know the right way to handle it while shucking. The hinge is the muscle that connects the top and bottom shells at the pointy end of the oyster. Opposite from the hinge is the rounded front of the oyster. The top of the oyster is the flatter shell. The bottom shell is cup-shaped.

Summary: Choose fresh oysters. Have the right supplies on hand. Understand oyster anatomy.

Your cat's changed behavior might be one of the first signs you notice that alerts you to a tail injury. Your cat may begin dragging his tail or keeping it low to the ground all the time, dribbling urine randomly, or having diarrhea. Your cat may begin walking unevenly or losing coordination in his back legs. Dribbling urine and having diarrhea are not symptoms of a broken tail on their own. If the tail injury was severe enough to cause these signs, the cat will definitely be dragging the tail. Gently feel along the length of the tail. Signs of injury or break include tender, swollen or bent areas. If you notice redness, tenderness, and swelling with fluid underneath, there may be an abscess, or pocket of pus, forming on your cat's tail. If there is exposed bone or if the skin has been stripped from the tail leaving only bone this is called a 'degloving' injury. If you happen to notice a hard, non-painful kink in your cat's tail, it's probably because he was born with the kink in the tail or it's an old, already healed injury. Never pull or try to remove a severed portion of tail since there are tough tendons and sensitive nerves. If you pull or stretch the tendons, you'll damage the use of the tail, hind limbs, bladder and bowel functions. It may also cause arterial bleeding, which is difficult to control and potentially life-threatening for your cat. The vet can address the injury without additional damage to the tail. Your cat may need a partial or full amputation of his tail if he has a degloving injury, deep cut, or if his tail is deeply or mostly severed. Your vet can also prescribe antibiotics to prevent infection which is highly likely with any open wound. Even if there are no external wounds, the vet can check your cat for other injuries. The vet may find neurologic damage from the tail being pulled during the accident. The vet will examine the tail for signs of physical or neurological damage. If the vet suspects nerve damage, your cat may have an electromyogram test. Anal sphincter and tail muscles are tested for nerve input. This lets the vet know if the tail will be able to recover. Your cat may still be in pain when you bring him to the vet's office. Stay close to him and speak in gentle comforting tones. You may want to loosely wrap your cat in a towel and place him in his carrier when you bring him to the vet's. This will calm him. Depending on where and how the tail is injured, your veterinarian will determine surgery or another treatment. If the tail is paralyzed, but your cat can still walk, the vet will probably amputate the tail. If the end of the tail has a break that's not causing problems for your cat, the vet may tell you to let it heal on its own. Your cat may need to stay at the veterinarian's for a few days to either rest and heal, or to determine the extent of the damage to the tail. If your cat's tail must be amputated, don't worry. It may take him a while to adjust to the lack of nerve sensation and change in balance. But, your cat will adapt to the change and his mobility won't suffer in the long run.
Summary: Watch your cat's behavior. Examine the cat's tail for injury. Take your cat to the vet if you suspect a tail injury. Understand treatments.