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Finding the Fourth Proportional to 820.34, 1,229.69 and 430.79

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Solution

The fourth proportional to 820.34, 1,229.69 and 430.79 is: 645.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.34 : 1,229.69 = 430.79 : x
  2. Step 2: Convert to fraction form
    820.34/1,229.69 = 430.79/x
  3. Step 3: Cross multiply
    820.34x = 1,229.69 × 430.79
  4. Step 4: Simplify right side
    820.34x = 529,733.08
  5. Step 5: Solve for x
    x = 529,733.08/820.34
  6. Step 6: Final answer
    x = 645.75

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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.