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Finding the Fourth Proportional to 391.21, 586.91 and 147.80

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Solution

The fourth proportional to 391.21, 586.91 and 147.80 is: 221.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.21 : 586.91 = 147.80 : x
  2. Step 2: Convert to fraction form
    391.21/586.91 = 147.80/x
  3. Step 3: Cross multiply
    391.21x = 586.91 × 147.80
  4. Step 4: Simplify right side
    391.21x = 86,746.03
  5. Step 5: Solve for x
    x = 86,746.03/391.21
  6. Step 6: Final answer
    x = 221.74

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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.