Finding the Fourth Proportional to 290,820.72, 436,218.72 and 91,136.70

Step by Step Solution

1. Step 1: Write the proportion equation
   290,820.72 : 436,218.72 = 91,136.70 : x
2. Step 2: Convert to fraction form
   290,820.72/436,218.72 = 91,136.70/x
3. Step 3: Cross multiply
   290,820.72x = 436,218.72 × 91,136.70
4. Step 4: Simplify right side
   290,820.72x = 39,755,534,619.02
5. Step 5: Solve for x
   x = 39,755,534,619.02/290,820.72
6. Step 6: Final answer
   x = 136,701.18