Finding the Fourth Proportional to 290,636.56, 435,796.76 and 90,870.80

Step by Step Solution

1. Step 1: Write the proportion equation
   290,636.56 : 435,796.76 = 90,870.80 : x
2. Step 2: Convert to fraction form
   290,636.56/435,796.76 = 90,870.80/x
3. Step 3: Cross multiply
   290,636.56x = 435,796.76 × 90,870.80
4. Step 4: Simplify right side
   290,636.56x = 39,601,200,218.61
5. Step 5: Solve for x
   x = 39,601,200,218.61/290,636.56
6. Step 6: Final answer
   x = 136,256.77