In quadrilateral ABDC, AB ∥ CD. Which additional piece of information is needed to determine that ABDC is a parallelogram? AB ≅ CD
AC ≅ BD
AB ⊥ BD
CD ⊥ BD

In the diagram below, dab and dac are adjacent angles. if mdac = 25°, what is mdab in degrees? what is mbac in degrees?

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.

In a certain city, the hourly wage of workers on temporary employment contracts is normally distributed. the mean is $15 and the standard deviation is $3. what percentage of temporary workers earn less than $12 per hour? a. 6% b. 16% c. 26% d. 36%