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Finding the Fourth Proportional to 820.30, 1,230.45 and 455.80

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Solution

The fourth proportional to 820.30, 1,230.45 and 455.80 is: 683.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.30 : 1,230.45 = 455.80 : x
  2. Step 2: Convert to fraction form
    820.30/1,230.45 = 455.80/x
  3. Step 3: Cross multiply
    820.30x = 1,230.45 × 455.80
  4. Step 4: Simplify right side
    820.30x = 560,839.11
  5. Step 5: Solve for x
    x = 560,839.11/820.30
  6. Step 6: Final answer
    x = 683.70

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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.