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Finding the Fourth Proportional to 660.40, 989.40 and 557.20

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Solution

The fourth proportional to 660.40, 989.40 and 557.20 is: 834.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.40 : 989.40 = 557.20 : x
  2. Step 2: Convert to fraction form
    660.40/989.40 = 557.20/x
  3. Step 3: Cross multiply
    660.40x = 989.40 × 557.20
  4. Step 4: Simplify right side
    660.40x = 551,293.68
  5. Step 5: Solve for x
    x = 551,293.68/660.40
  6. Step 6: Final answer
    x = 834.79

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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.