X=10 Y=1.25; X=8 Y=1; X=6 Y=0.75; X=4 Y=0.5
Answer:

Step-by-step explanation:
Subtract 13 from 17 to get the length of the base. Then add the 1, 1, and 3 together to get the height. Then you use the area formula for a triangle.
The expression (n+3) represents the measure of an exterior angle of a regular octadecagonal.
Answer:
7
Step-by-step explanation:
median is the number at the center of the rest
3,1,8], 7 [,6,5,1