First, a triangle pattern is identified as defined by your trade plan. Generally, with a symmetrical trade plan you'll notice a “squeeze” where there are a series higher-lows and lower-highs which close in.
When you draw a line on each, you will have a triangle pattern.
Second, traders use a triangle pattern to measure their risk and profit levels. They measure the base of the triangle (the green line in this image).
It is plotted where the trader believes price is likely to break out of the triangle pattern.
The “minimum price target” is where targets will generally aim to target. In practice, when working with triangle patterns, some traders aim lower than that point or scale out from there and keep a floating position.
The stop loss is usually below the triangle and trailed along the triangle pattern.