What percentage is the shaded area

Find the required measurements of the following trapezoids. a = 8 cm b = 16 cm h = 10 cm

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

When the ball has traveled a distance of