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Finding the Fourth Proportional to 561.40, 840.90 and 489.40

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Solution

The fourth proportional to 561.40, 840.90 and 489.40 is: 733.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    561.40 : 840.90 = 489.40 : x
  2. Step 2: Convert to fraction form
    561.40/840.90 = 489.40/x
  3. Step 3: Cross multiply
    561.40x = 840.90 × 489.40
  4. Step 4: Simplify right side
    561.40x = 411,536.46
  5. Step 5: Solve for x
    x = 411,536.46/561.40
  6. Step 6: Final answer
    x = 733.05

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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.