11)
keeping in mind that, there are 3 feet in 1 yard, therefore, in 4 yards there are 4(3) feet or 12 feet.
now, 12 feet is twice as much as 6 feet. If the original grid, had each unit length to be 6 feet, that means each square was a 6x6 square. That means the new adjusted grid, will be twice as many feet per each unit, namely a 12 : 1. Check the first picture below.
12)
check the second picture below, that's the 30-60-90 rule.
now, if one angle in the triangle is 30°, and another is 60
°, the last one must be a 90° angle, so the triangle is a 30-60-90 triangle, and thus the 30-60-90 rule applies, with the ratios as you see in the picture.
so, if any of the sides has a value of 6, that will be a constraint to the other sides, since the other sides must be at a ratio of 6.
because of those ratios constraints, you can only make one unique triangle, if one side is 6, the others cannot fluctuate in length, they must be at a ratio of 6.
