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Finding the Fourth Proportional to 813.12, 1,219.80 and 402.72

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Solution

The fourth proportional to 813.12, 1,219.80 and 402.72 is: 604.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.12 : 1,219.80 = 402.72 : x
  2. Step 2: Convert to fraction form
    813.12/1,219.80 = 402.72/x
  3. Step 3: Cross multiply
    813.12x = 1,219.80 × 402.72
  4. Step 4: Simplify right side
    813.12x = 491,237.86
  5. Step 5: Solve for x
    x = 491,237.86/813.12
  6. Step 6: Final answer
    x = 604.14

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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.