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Finding the Fourth Proportional to 439.74, 662.40 and 428.81

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Solution

The fourth proportional to 439.74, 662.40 and 428.81 is: 645.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.74 : 662.40 = 428.81 : x
  2. Step 2: Convert to fraction form
    439.74/662.40 = 428.81/x
  3. Step 3: Cross multiply
    439.74x = 662.40 × 428.81
  4. Step 4: Simplify right side
    439.74x = 284,040.43
  5. Step 5: Solve for x
    x = 284,040.43/439.74
  6. Step 6: Final answer
    x = 645.93

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.