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Finding the Fourth Proportional to 820.32, 1,229.28 and 647.42

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Solution

The fourth proportional to 820.32, 1,229.28 and 647.42 is: 970.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.32 : 1,229.28 = 647.42 : x
  2. Step 2: Convert to fraction form
    820.32/1,229.28 = 647.42/x
  3. Step 3: Cross multiply
    820.32x = 1,229.28 × 647.42
  4. Step 4: Simplify right side
    820.32x = 795,860.46
  5. Step 5: Solve for x
    x = 795,860.46/820.32
  6. Step 6: Final answer
    x = 970.18

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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.