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Finding the Fourth Proportional to 813.84, 1,221.06 and 380.69

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Solution

The fourth proportional to 813.84, 1,221.06 and 380.69 is: 571.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.84 : 1,221.06 = 380.69 : x
  2. Step 2: Convert to fraction form
    813.84/1,221.06 = 380.69/x
  3. Step 3: Cross multiply
    813.84x = 1,221.06 × 380.69
  4. Step 4: Simplify right side
    813.84x = 464,845.33
  5. Step 5: Solve for x
    x = 464,845.33/813.84
  6. Step 6: Final answer
    x = 571.18

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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.