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Finding the Fourth Proportional to 391.70, 540.57 and 217.05

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Solution

The fourth proportional to 391.70, 540.57 and 217.05 is: 299.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.70 : 540.57 = 217.05 : x
  2. Step 2: Convert to fraction form
    391.70/540.57 = 217.05/x
  3. Step 3: Cross multiply
    391.70x = 540.57 × 217.05
  4. Step 4: Simplify right side
    391.70x = 117,329.51
  5. Step 5: Solve for x
    x = 117,329.51/391.70
  6. Step 6: Final answer
    x = 299.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.