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Finding the Fourth Proportional to 611.40, 916.98 and 391.35

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Solution

The fourth proportional to 611.40, 916.98 and 391.35 is: 586.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.40 : 916.98 = 391.35 : x
  2. Step 2: Convert to fraction form
    611.40/916.98 = 391.35/x
  3. Step 3: Cross multiply
    611.40x = 916.98 × 391.35
  4. Step 4: Simplify right side
    611.40x = 358,860.12
  5. Step 5: Solve for x
    x = 358,860.12/611.40
  6. Step 6: Final answer
    x = 586.95

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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.