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Finding the Fourth Proportional to 261.47, 391.91 and 145.89

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Solution

The fourth proportional to 261.47, 391.91 and 145.89 is: 218.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.47 : 391.91 = 145.89 : x
  2. Step 2: Convert to fraction form
    261.47/391.91 = 145.89/x
  3. Step 3: Cross multiply
    261.47x = 391.91 × 145.89
  4. Step 4: Simplify right side
    261.47x = 57,175.02
  5. Step 5: Solve for x
    x = 57,175.02/261.47
  6. Step 6: Final answer
    x = 218.67

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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.