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Finding the Fourth Proportional to 840.60, 1,260.90 and 686.70

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Solution

The fourth proportional to 840.60, 1,260.90 and 686.70 is: 1,030.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.60 : 1,260.90 = 686.70 : x
  2. Step 2: Convert to fraction form
    840.60/1,260.90 = 686.70/x
  3. Step 3: Cross multiply
    840.60x = 1,260.90 × 686.70
  4. Step 4: Simplify right side
    840.60x = 865,860.03
  5. Step 5: Solve for x
    x = 865,860.03/840.60
  6. Step 6: Final answer
    x = 1,030.05

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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.