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Finding the Fourth Proportional to 1,388.64, 2,082.78 and 658.68

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Solution

The fourth proportional to 1,388.64, 2,082.78 and 658.68 is: 987.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.64 : 2,082.78 = 658.68 : x
  2. Step 2: Convert to fraction form
    1,388.64/2,082.78 = 658.68/x
  3. Step 3: Cross multiply
    1,388.64x = 2,082.78 × 658.68
  4. Step 4: Simplify right side
    1,388.64x = 1,371,885.53
  5. Step 5: Solve for x
    x = 1,371,885.53/1,388.64
  6. Step 6: Final answer
    x = 987.93

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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.