Finding the Fourth Proportional to 290,987.33, 436,499.45 and 91,315.59

Step by Step Solution

1. Step 1: Write the proportion equation
   290,987.33 : 436,499.45 = 91,315.59 : x
2. Step 2: Convert to fraction form
   290,987.33/436,499.45 = 91,315.59/x
3. Step 3: Cross multiply
   290,987.33x = 436,499.45 × 91,315.59
4. Step 4: Simplify right side
   290,987.33x = 39,859,204,811.43
5. Step 5: Solve for x
   x = 39,859,204,811.43/290,987.33
6. Step 6: Final answer
   x = 136,979.18