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Step-by-step explanation:

Let alpha be the unknown angle. We can set up our sine law as follows:

or

Solving for alpha,

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.

for this case we must apply distributive property to the following expression:

the distributive property states that:

then, when applying the property we have to multiply the -2 for each term within the parenthesis: