Answer:
12
Step-by-step explanation:
It is worthwhile memorizing the ratios of legs in a 30°–60°–90° triangle. Shortest to longest, the ratios are ...
1 : √3 : 2
Then the sides marked will have the ratio ...
6 : x = 1 : 2 = 6 : 12
x = 12
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You can also get there using trigonometry.
cos(60°) = 6/x
x = 60/cos(60° = 60/0.5
x = 12
