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Explanation:
We can find x using the law of sines, but first we need to find the missing angle. Let's call that y for now. The three angles of any triangle add to 180, so,
23+146+y = 180
169+y = 180
y = 180-169
y = 11
The missing interior angle is 11 degrees.
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Now we can apply the law of sines.
sin(23)/x = sin(11)/7
7*sin(23) = x*sin(11)
x*sin(11) = 7*sin(23)
x = 7*sin(23)/sin(11)
x = 14.3343236728824
x = 14.3
Make sure your calculator is in degree mode.