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Finding the Fourth Proportional to 391.80, 587.70 and 380.28

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Solution

The fourth proportional to 391.80, 587.70 and 380.28 is: 570.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.80 : 587.70 = 380.28 : x
  2. Step 2: Convert to fraction form
    391.80/587.70 = 380.28/x
  3. Step 3: Cross multiply
    391.80x = 587.70 × 380.28
  4. Step 4: Simplify right side
    391.80x = 223,490.56
  5. Step 5: Solve for x
    x = 223,490.56/391.80
  6. Step 6: Final answer
    x = 570.42

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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.