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Finding the Fourth Proportional to 821.85, 1,230.66 and 456.21

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Solution

The fourth proportional to 821.85, 1,230.66 and 456.21 is: 683.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.85 : 1,230.66 = 456.21 : x
  2. Step 2: Convert to fraction form
    821.85/1,230.66 = 456.21/x
  3. Step 3: Cross multiply
    821.85x = 1,230.66 × 456.21
  4. Step 4: Simplify right side
    821.85x = 561,439.40
  5. Step 5: Solve for x
    x = 561,439.40/821.85
  6. Step 6: Final answer
    x = 683.14

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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.