Student ID numbers are 5 digits. The first digit of the ID number cannot be 0 and all of the digits of the ID number cannot be the same. How many possible ID numbers are possible?

Will give are given that xy is parallel to zw. if xz is a transversal that intercepts xy and zw, angle angle alternate interior angles. since xy is parallel to zw, we know that these angles are we also know that angle xvy and angle zvw are , and thus congruent. we can conclude that △xyv ~ △zwv using the similarity theorem.

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?

The figure below shows rectangle abcd and the triangle eca on a coordinate plane.which of the following expressions represents the perimeter of triangle of triangle eca in units