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Finding the Fourth Proportional to 813.84, 1,220.31 and 380.58

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Solution

The fourth proportional to 813.84, 1,220.31 and 380.58 is: 570.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.84 : 1,220.31 = 380.58 : x
  2. Step 2: Convert to fraction form
    813.84/1,220.31 = 380.58/x
  3. Step 3: Cross multiply
    813.84x = 1,220.31 × 380.58
  4. Step 4: Simplify right side
    813.84x = 464,425.58
  5. Step 5: Solve for x
    x = 464,425.58/813.84
  6. Step 6: Final answer
    x = 570.66

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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.