4. Construct the bisectors of the three angles of a triangle. Repeat for several triangles. If your construction is cor- rect, these bisectors will pass through the same point.

15.5 feets of lumber

Step-by-step explanation:

To build a window frame :

Length of lumber needed = 4 3/4 feets and 3 feets

Number of 4 3/4 feets lumber needed = 2

Number of 3 feets lumber needed = 2

Total required lumber :

(2 * 4 3/4)feets + (2 * 3) feets

(2 * 19/4) feets + 6 feets

9.5 feets + 6 feets

= 15.5 feets