15 points!! m ABC + mBAC + m ACB
when ABC is an isosceles triangle with AB=AC
mABC when mBAC = 70°
and ABC is an isosceles triangle with
AB=AC
mZQPR when mZQRP = 30°
and APQR is an isosceles triangle with
PQ = QR
mZBDE when mZBAC = 45°
and points D and E are the midpoints
AB and BC, respectively, in AABC

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”?