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Finding the Fourth Proportional to 821.98, 1,230.58 and 431.06

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Solution

The fourth proportional to 821.98, 1,230.58 and 431.06 is: 645.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.98 : 1,230.58 = 431.06 : x
  2. Step 2: Convert to fraction form
    821.98/1,230.58 = 431.06/x
  3. Step 3: Cross multiply
    821.98x = 1,230.58 × 431.06
  4. Step 4: Simplify right side
    821.98x = 530,445.78
  5. Step 5: Solve for x
    x = 530,445.78/821.98
  6. Step 6: Final answer
    x = 645.33

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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.