20 is the adjacent and x is the opposite in the triangle and 6° is the angle,
using S(in) O(pposite) H( hypotenuse) COH TOA this is how my school teaches us to remember what to use. to find which to use look at the last two letters of the "word" as this tell you the part of the triangle 1 which you already have in this example 20 (A) and the other that you are going to find or x (O). the one that uses both o and a is tan.
tan = opposite divided by the adjacent.
tan= (opposite)
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20
20 × tan(6° =2.1 cm
because we don't have the opposite value instead we times tan and the angle by 20.