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Finding the Fourth Proportional to 787.34, 1,087.70 and 518.80

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Solution

The fourth proportional to 787.34, 1,087.70 and 518.80 is: 716.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.34 : 1,087.70 = 518.80 : x
  2. Step 2: Convert to fraction form
    787.34/1,087.70 = 518.80/x
  3. Step 3: Cross multiply
    787.34x = 1,087.70 × 518.80
  4. Step 4: Simplify right side
    787.34x = 564,298.76
  5. Step 5: Solve for x
    x = 564,298.76/787.34
  6. Step 6: Final answer
    x = 716.72

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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.