Given that MT is the diameter of circle P and intersects chord DR at E with m∠TED = 90°, you can deduce the following key points based on the properties of circles:
- A diameter that intersects a chord at a right angle (90 degrees) implies that the point of intersection (E) is the midpoint of the chord (DR).
Since E is the midpoint of DR, we can conclude that:
- ED ≅ ER (the segments from E to D and from E to R are equal).
As for the other statements provided, here’s an analysis:
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EM ≅ ET: This statement cannot be concluded just from the information provided. We do not have enough data to prove that EM and ET are congruent.
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MD ≅ TD: This statement cannot be established directly since we don't have information that relates specifically to segments MD and TD
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m∠MET = 90°: This statement is also not guaranteed based on the information about E.
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ED ≅ ER: This is true. As previously discussed, E is the midpoint of chord DR, therefore ED is congruent to ER.
Thus, the statement that must also be true is:
ED ≅ ER.