Select all unbiased estimators from the following list: -standard deviation
-mean
-variance
-range
-median
-proportion

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation:

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step-by-step explanation:

ever thing time 1 is a multiply by 1 it get  

the answer is d

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