Answer:
?=9
Step-by-step explanation:
We have a special right triangle, the 45-45-90 triangle.
In a 45-45-90 triangle, the side lengths are x, and the hypotenuse is x√2.
Since we know that the side length is 9, this means that:

The ? is 9.
Answer:
Each interior angle = 135 degrees,
Step-by-step explanation:
The exterior angles of all convex polygons add up to 360 degrees.
So for a regular octagon each exterior angle = 360 / 8
= 45 degrees.
Therefore each interior angle = 180 - 45 = 135 degrees,
Answer:
d
Step-by-step explanation: