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Finding the Fourth Proportional to 787.20, 1,180.80 and 457.80

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Solution

The fourth proportional to 787.20, 1,180.80 and 457.80 is: 686.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.20 : 1,180.80 = 457.80 : x
  2. Step 2: Convert to fraction form
    787.20/1,180.80 = 457.80/x
  3. Step 3: Cross multiply
    787.20x = 1,180.80 × 457.80
  4. Step 4: Simplify right side
    787.20x = 540,570.24
  5. Step 5: Solve for x
    x = 540,570.24/787.20
  6. Step 6: Final answer
    x = 686.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.