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Finding the Fourth Proportional to 814.88, 1,221.20 and 429.68

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Solution

The fourth proportional to 814.88, 1,221.20 and 429.68 is: 643.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.88 : 1,221.20 = 429.68 : x
  2. Step 2: Convert to fraction form
    814.88/1,221.20 = 429.68/x
  3. Step 3: Cross multiply
    814.88x = 1,221.20 × 429.68
  4. Step 4: Simplify right side
    814.88x = 524,725.22
  5. Step 5: Solve for x
    x = 524,725.22/814.88
  6. Step 6: Final answer
    x = 643.93

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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.