∠C and ∠D are vertical angles with m∠C=−2x+90 and m∠D=x−30 . What is m∠D?
1 answer:
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Answer:
The correct option is C
Step-by-step explanation:
I attached an image that forms the complete question.
The converse Pythagorean theorem states that, "If the square of the longest side of a triangle is equal to the square of the other two sides, then the triangle is a right triangle."
That is if c is the longest side of a triangle and then a and b are the other sides, then if,
c² = a² + b², the triangle is a right triangle.
Looking at all the options, option C fits the theorem well. Because
3² + 4² = 5² implies the triangle is a right triangle and the converse theorem is established.
The option D also looks close, but it's not correct because you can just draw any two sides and put the right angle in between them. The longest is always the part of the triangle that is opposite to the right angle, 90°. If for instance, you draw 3 and 5 then put the right angle in between them, 4 will take the position of the longest side which is wrong.
Therefore, the correct option is c.
