Finding the Fourth Proportional to 42,787.08, 64,157.12 and 13,196.70

Step by Step Solution

1. Step 1: Write the proportion equation
   42,787.08 : 64,157.12 = 13,196.70 : x
2. Step 2: Convert to fraction form
   42,787.08/64,157.12 = 13,196.70/x
3. Step 3: Cross multiply
   42,787.08x = 64,157.12 × 13,196.70
4. Step 4: Simplify right side
   42,787.08x = 846,662,265.50
5. Step 5: Solve for x
   x = 846,662,265.50/42,787.08
6. Step 6: Final answer
   x = 19,787.80