Finding the Fourth Proportional to 1,915.61, 2,641.88 and 1,721.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.61 : 2,641.88 = 1,721.21 : x
2. Step 2: Convert to fraction form
   1,915.61/2,641.88 = 1,721.21/x
3. Step 3: Cross multiply
   1,915.61x = 2,641.88 × 1,721.21
4. Step 4: Simplify right side
   1,915.61x = 4,547,221.37
5. Step 5: Solve for x
   x = 4,547,221.37/1,915.61
6. Step 6: Final answer
   x = 2,373.78