Ineed on this problem asap pls me.

Need on this geometry question. explain how you did it.

Plz ( true - false) all triangles have interior angles whose measure sum to 90.

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?