Answer:
Step-by-step explanation:
You can simply count the number of unit cubes.
There are 11 cubic units.
9 students, 4 are selected and order doesn't matter:
Go to the 9th row of the triangle (mind you the first row is 0), the 2nd is 1st row
9th row: 1 9 36 84 126 126 84 36 9 1
Now choose the 4th column (excluding the 1st , you will get 126 :
so 126 is the number of combination requested:
PROOF: ⁹C₄ = 9!/(9-4)! .4! = (9!)/5!.4! = 126
Answer:
the answer; 32÷36×100 will give the answer (d) -88.9%
If the span is 16-ft, then the half-span is 8-ft.
Pitch = (rise) / (half-span) = 6/8 = 3/4 or 0.75 or 75% .
That's a VERY steep roof !
