Finding the Fourth Proportional to 105.71, 145.76 and 91.00

Step by Step Solution

1. Step 1: Write the proportion equation
   105.71 : 145.76 = 91.00 : x
2. Step 2: Convert to fraction form
   105.71/145.76 = 91.00/x
3. Step 3: Cross multiply
   105.71x = 145.76 × 91.00
4. Step 4: Simplify right side
   105.71x = 13,263.43
5. Step 5: Solve for x
   x = 13,263.43/105.71
6. Step 6: Final answer
   x = 125.48