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Finding the Fourth Proportional to 391.56, 587.40 and 135

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Solution

The fourth proportional to 391.56, 587.40 and 135 is: 202.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.56 : 587.40 = 135 : x
  2. Step 2: Convert to fraction form
    391.56/587.40 = 135/x
  3. Step 3: Cross multiply
    391.56x = 587.40 × 135
  4. Step 4: Simplify right side
    391.56x = 79,299
  5. Step 5: Solve for x
    x = 79,299/391.56
  6. Step 6: Final answer
    x = 202.52

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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.