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Finding the Fourth Proportional to 814.16, 1,220.70 and 428.60

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Solution

The fourth proportional to 814.16, 1,220.70 and 428.60 is: 642.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.16 : 1,220.70 = 428.60 : x
  2. Step 2: Convert to fraction form
    814.16/1,220.70 = 428.60/x
  3. Step 3: Cross multiply
    814.16x = 1,220.70 × 428.60
  4. Step 4: Simplify right side
    814.16x = 523,192.02
  5. Step 5: Solve for x
    x = 523,192.02/814.16
  6. Step 6: Final answer
    x = 642.62

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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.