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Finding the Fourth Proportional to 1,213.56, 1,820.19 and 391.88

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Solution

The fourth proportional to 1,213.56, 1,820.19 and 391.88 is: 587.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,213.56 : 1,820.19 = 391.88 : x
  2. Step 2: Convert to fraction form
    1,213.56/1,820.19 = 391.88/x
  3. Step 3: Cross multiply
    1,213.56x = 1,820.19 × 391.88
  4. Step 4: Simplify right side
    1,213.56x = 713,286.96
  5. Step 5: Solve for x
    x = 713,286.96/1,213.56
  6. Step 6: Final answer
    x = 587.76

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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.