The diagonals of a trapezoid are equal. always sometimes never

Suppose the radius of a circle is 16. what issuppose the radius of a circle is 16. what is its circumference its circumference

Hurry and answer this! circle x with a radius of 6 units and circle y with a radius of 2 units are shown which steps would prove the circles similar? translate the circles so they share a common center point, and dilate circle y by a scale factor of 4. translate the circles so the center of one circle rests on the edge of the other circle, and dilate circle y by a scale factor of 4. translate the circles so they share a common center point, and dilate circle y by a scale factor of 3. translate the circles so the center of one circle rests on the edge of the other circle, and dilate circle y by a scale factor of 3

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.