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Finding the Fourth Proportional to 391.21, 585.72 and 253.91

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Solution

The fourth proportional to 391.21, 585.72 and 253.91 is: 380.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.21 : 585.72 = 253.91 : x
  2. Step 2: Convert to fraction form
    391.21/585.72 = 253.91/x
  3. Step 3: Cross multiply
    391.21x = 585.72 × 253.91
  4. Step 4: Simplify right side
    391.21x = 148,720.17
  5. Step 5: Solve for x
    x = 148,720.17/391.21
  6. Step 6: Final answer
    x = 380.15

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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.