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Finding the Fourth Proportional to 1,213.50, 1,820.40 and 391.76

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Solution

The fourth proportional to 1,213.50, 1,820.40 and 391.76 is: 587.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,213.50 : 1,820.40 = 391.76 : x
  2. Step 2: Convert to fraction form
    1,213.50/1,820.40 = 391.76/x
  3. Step 3: Cross multiply
    1,213.50x = 1,820.40 × 391.76
  4. Step 4: Simplify right side
    1,213.50x = 713,150.80
  5. Step 5: Solve for x
    x = 713,150.80/1,213.50
  6. Step 6: Final answer
    x = 587.68

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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.