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Finding the Fourth Proportional to 1,138.66, 1,708 and 489.40

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Solution

The fourth proportional to 1,138.66, 1,708 and 489.40 is: 734.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.66 : 1,708 = 489.40 : x
  2. Step 2: Convert to fraction form
    1,138.66/1,708 = 489.40/x
  3. Step 3: Cross multiply
    1,138.66x = 1,708 × 489.40
  4. Step 4: Simplify right side
    1,138.66x = 835,895.20
  5. Step 5: Solve for x
    x = 835,895.20/1,138.66
  6. Step 6: Final answer
    x = 734.10

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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.