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Finding the Fourth Proportional to 820.42, 1,230.90 and 647.17

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Solution

The fourth proportional to 820.42, 1,230.90 and 647.17 is: 970.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.42 : 1,230.90 = 647.17 : x
  2. Step 2: Convert to fraction form
    820.42/1,230.90 = 647.17/x
  3. Step 3: Cross multiply
    820.42x = 1,230.90 × 647.17
  4. Step 4: Simplify right side
    820.42x = 796,601.55
  5. Step 5: Solve for x
    x = 796,601.55/820.42
  6. Step 6: Final answer
    x = 970.97

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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.