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Finding the Fourth Proportional to 391.64, 587.04 and 209.15

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Solution

The fourth proportional to 391.64, 587.04 and 209.15 is: 313.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.64 : 587.04 = 209.15 : x
  2. Step 2: Convert to fraction form
    391.64/587.04 = 209.15/x
  3. Step 3: Cross multiply
    391.64x = 587.04 × 209.15
  4. Step 4: Simplify right side
    391.64x = 122,779.42
  5. Step 5: Solve for x
    x = 122,779.42/391.64
  6. Step 6: Final answer
    x = 313.50

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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.