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Finding the Fourth Proportional to 840.38, 1,258.95 and 686.48

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Solution

The fourth proportional to 840.38, 1,258.95 and 686.48 is: 1,028.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.38 : 1,258.95 = 686.48 : x
  2. Step 2: Convert to fraction form
    840.38/1,258.95 = 686.48/x
  3. Step 3: Cross multiply
    840.38x = 1,258.95 × 686.48
  4. Step 4: Simplify right side
    840.38x = 864,244.00
  5. Step 5: Solve for x
    x = 864,244.00/840.38
  6. Step 6: Final answer
    x = 1,028.40

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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.