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Finding the Fourth Proportional to 820.70, 1,230.18 and 409.02

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Solution

The fourth proportional to 820.70, 1,230.18 and 409.02 is: 613.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.70 : 1,230.18 = 409.02 : x
  2. Step 2: Convert to fraction form
    820.70/1,230.18 = 409.02/x
  3. Step 3: Cross multiply
    820.70x = 1,230.18 × 409.02
  4. Step 4: Simplify right side
    820.70x = 503,168.22
  5. Step 5: Solve for x
    x = 503,168.22/820.70
  6. Step 6: Final answer
    x = 613.10

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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.