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Finding the Fourth Proportional to 1,215.01, 1,820.78 and 939.81

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Solution

The fourth proportional to 1,215.01, 1,820.78 and 939.81 is: 1,408.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,215.01 : 1,820.78 = 939.81 : x
  2. Step 2: Convert to fraction form
    1,215.01/1,820.78 = 939.81/x
  3. Step 3: Cross multiply
    1,215.01x = 1,820.78 × 939.81
  4. Step 4: Simplify right side
    1,215.01x = 1,711,187.25
  5. Step 5: Solve for x
    x = 1,711,187.25/1,215.01
  6. Step 6: Final answer
    x = 1,408.37

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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.