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Finding the Fourth Proportional to 813.72, 1,220.23 and 505.11

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Solution

The fourth proportional to 813.72, 1,220.23 and 505.11 is: 757.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.72 : 1,220.23 = 505.11 : x
  2. Step 2: Convert to fraction form
    813.72/1,220.23 = 505.11/x
  3. Step 3: Cross multiply
    813.72x = 1,220.23 × 505.11
  4. Step 4: Simplify right side
    813.72x = 616,350.38
  5. Step 5: Solve for x
    x = 616,350.38/813.72
  6. Step 6: Final answer
    x = 757.45

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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.