There are 3 bacis types of Triangles:
Ascending
Descending
Symmetrical
Ascending Triangle
Is formed especially in an Uptrend. The Uptrend seems to slow-down first then begins to stagnate. It dashes against the Resistance, where the horizontal line is formed. This pattern can be identifiied by the Triangle shape.
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The price oscillates in the Triangle borders and gradually approaches the narrower part. In this part it breaks through the triangle. After the breakthrough the move is usually very strong, so we should better catch the trend immediately. The Triangle is also broken somewhere about 2/3 or 3/4 of its length. The price should continue in its previous trend, after the Resistance breakthrough. But it isn't always true. Sometimes it just can't break the resistance and begins to fall, instead. Some traders use the SBBA order - Sell Bellow, Buy Above. They Sell if the price crosses a previous defined level and Buy if it crosses another one.
Descending Triangle
Descending Triangle is an opposite to the Ascending triangle. Its angle is different. It mostly formes during a Downtrend.
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The Descending Triangle is formed by a slow-down of a trend, so it forms a new Support. After the Support is being overcame, the price should continue in its previous decrease. But this is not an immutable rule. If the price can't break the Support, it can turn up and start to rise. The traders use to wait for a direction it decides to go in. They use the SBBA order, (Sell below, Buy above), as well.
Symmetrical Triangle
Symmetrical Triangle is a combination of the Triangles mentioned before. The price oscillates in the Symmetrical triangle, among its sides, while Support and Resistance converge each other. The price usually breaks through the triangle somewhere in the 2/3 or 3/4 of the pattern. Then it becomes to rise or fall strongly in the chosen direction.
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Unlike the Ascending or Descending Triangle, there are just general recommendations for the Symmetrical one. The price can begin to rise or fall - in both directions. The smart traders use to wait whether Bulls or Bears win. After the triangle breakthrough the traders join the winners and strenghten so the prevailing trend even more.
The Stop Loss can be placed near the triangle side, which has been crossed. It applies to all of the Triangles.
Note: The Triangles are quite rare pattern of technical analysis. Their disadvantage is that they are hard enough to identify in the price chart. First, the traders must get used to them to find and trade them.