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Finding the Fourth Proportional to 911.40, 1,257.70 and 497.40

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Solution

The fourth proportional to 911.40, 1,257.70 and 497.40 is: 686.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.40 : 1,257.70 = 497.40 : x
  2. Step 2: Convert to fraction form
    911.40/1,257.70 = 497.40/x
  3. Step 3: Cross multiply
    911.40x = 1,257.70 × 497.40
  4. Step 4: Simplify right side
    911.40x = 625,579.98
  5. Step 5: Solve for x
    x = 625,579.98/911.40
  6. Step 6: Final answer
    x = 686.39

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1.5x scale

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.