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Finding the Fourth Proportional to 728.30, 1,091.40 and 380.88

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Solution

The fourth proportional to 728.30, 1,091.40 and 380.88 is: 570.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.30 : 1,091.40 = 380.88 : x
  2. Step 2: Convert to fraction form
    728.30/1,091.40 = 380.88/x
  3. Step 3: Cross multiply
    728.30x = 1,091.40 × 380.88
  4. Step 4: Simplify right side
    728.30x = 415,692.43
  5. Step 5: Solve for x
    x = 415,692.43/728.30
  6. Step 6: Final answer
    x = 570.77

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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.