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Finding the Fourth Proportional to 1,239.15, 1,856.70 and 911.10

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Solution

The fourth proportional to 1,239.15, 1,856.70 and 911.10 is: 1,365.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.15 : 1,856.70 = 911.10 : x
  2. Step 2: Convert to fraction form
    1,239.15/1,856.70 = 911.10/x
  3. Step 3: Cross multiply
    1,239.15x = 1,856.70 × 911.10
  4. Step 4: Simplify right side
    1,239.15x = 1,691,639.37
  5. Step 5: Solve for x
    x = 1,691,639.37/1,239.15
  6. Step 6: Final answer
    x = 1,365.16

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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.