Hi there! In this problem, you should have the knowledge of three basic Trigonometric Ratio.
- sinA = opposite/hypotenuse
- cosA = adjacent/hypotenuse
- tanA = opposite/adjacent
Now that we know three basic ratio. Let's check each choices!
This choice is wrong because we focus on the 50° angle. When we focus on 50°, sin50° should be d/x and not d/c.
This choice is also wrong because in ratio, it's cos50° that adjacent/hypotenuse.
This choice is correct! As ratio states, tanA = opposite/adjacent.
This choice is wrong. x/c is a reciprocal of cosine which is 1/cos. We call the reciprocal of cosine as secant or sec in short.
This choice is wrong as x/d is a reciprocal of sine which is 1/sin. We call the reciprocal of sine as cosecant or cosec/csc in short.
This choice is right by the ratio. Nothing really much to explain since we follow by ratio that is defined.
Answer
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Furthermore, tan also has its reciprocal form itself which is called cotangent also known as cot in short.
Hope this helps, and Happy Learning! :)
