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Finding the Fourth Proportional to 813.52, 1,220.28 and 428.32

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Solution

The fourth proportional to 813.52, 1,220.28 and 428.32 is: 642.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.52 : 1,220.28 = 428.32 : x
  2. Step 2: Convert to fraction form
    813.52/1,220.28 = 428.32/x
  3. Step 3: Cross multiply
    813.52x = 1,220.28 × 428.32
  4. Step 4: Simplify right side
    813.52x = 522,670.33
  5. Step 5: Solve for x
    x = 522,670.33/813.52
  6. Step 6: Final answer
    x = 642.48

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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.