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Finding the Fourth Proportional to 261.60, 391.32 and 213

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Solution

The fourth proportional to 261.60, 391.32 and 213 is: 318.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.60 : 391.32 = 213 : x
  2. Step 2: Convert to fraction form
    261.60/391.32 = 213/x
  3. Step 3: Cross multiply
    261.60x = 391.32 × 213
  4. Step 4: Simplify right side
    261.60x = 83,351.16
  5. Step 5: Solve for x
    x = 83,351.16/261.60
  6. Step 6: Final answer
    x = 318.62

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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.