Answer:
x = 3
Explanation:
Once again we want to use the relationship stated earlier
Where A * B = C * D
Once again imagine that the segments in the given problem have letters
A = x
B = 12
C = x + 1
D = 9
Now we create an equation using the relationship
12 * x = 9(x+1)
now we solve using basic algebra
step 1 distribute the 9 to the x and the 1
9 * x = 9x
9 * 1 = 9
now we have 12x = 9x + 9
step 2 subtract 9x from each side
12x - 9x = 3x
9x - 9x cancels out
now we have 3x = 9
step 3 divide each side by 3
3x/3=x
9/3=3
we're left with x = 3