Answer:
b = 6 sqrt(2)
Step-by-step explanation:
Since this is right triangle, we can use the Pythagorean theorem
a^2+b^2 = c^2 where a and b are the legs and c is the hypotenuse
3^2 + b^2 = 9^2
9+b^2 = 81
b^2 = 81-9
b^2 = 72
Take the square root of each side
sqrt(b^2) = sqrt(72)
b = sqrt(36*2)
b = 6 sqrt(2)
Answer:

Step-by-step explanation:
Formula for the perimeter of a rectangle: 
The total is 6400, but if subtracted, its 1400
Answer:
B
Step-by-step explanation:
Let x = total distance he covered
3x/4 by bus
1/2 . x/4 = x/8 by jogging
the remaining distance = x/8 by walking
thus x/8 = 800ft
x = 8 . 800 = 6400ft