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Finding the Fourth Proportional to 391.55, 586.66 and 218.18

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Solution

The fourth proportional to 391.55, 586.66 and 218.18 is: 326.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.55 : 586.66 = 218.18 : x
  2. Step 2: Convert to fraction form
    391.55/586.66 = 218.18/x
  3. Step 3: Cross multiply
    391.55x = 586.66 × 218.18
  4. Step 4: Simplify right side
    391.55x = 127,995.51
  5. Step 5: Solve for x
    x = 127,995.51/391.55
  6. Step 6: Final answer
    x = 326.89

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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.