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Finding the Fourth Proportional to 813.64, 1,220.61 and 265.81

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Solution

The fourth proportional to 813.64, 1,220.61 and 265.81 is: 398.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.64 : 1,220.61 = 265.81 : x
  2. Step 2: Convert to fraction form
    813.64/1,220.61 = 265.81/x
  3. Step 3: Cross multiply
    813.64x = 1,220.61 × 265.81
  4. Step 4: Simplify right side
    813.64x = 324,450.34
  5. Step 5: Solve for x
    x = 324,450.34/813.64
  6. Step 6: Final answer
    x = 398.76

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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.