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Finding the Fourth Proportional to 787.28, 1,086.50 and 455.80

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Solution

The fourth proportional to 787.28, 1,086.50 and 455.80 is: 629.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.28 : 1,086.50 = 455.80 : x
  2. Step 2: Convert to fraction form
    787.28/1,086.50 = 455.80/x
  3. Step 3: Cross multiply
    787.28x = 1,086.50 × 455.80
  4. Step 4: Simplify right side
    787.28x = 495,226.70
  5. Step 5: Solve for x
    x = 495,226.70/787.28
  6. Step 6: Final answer
    x = 629.04

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.