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Finding the Fourth Proportional to 145.48, 217.86 and 81.40

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Solution

The fourth proportional to 145.48, 217.86 and 81.40 is: 121.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.48 : 217.86 = 81.40 : x
  2. Step 2: Convert to fraction form
    145.48/217.86 = 81.40/x
  3. Step 3: Cross multiply
    145.48x = 217.86 × 81.40
  4. Step 4: Simplify right side
    145.48x = 17,733.80
  5. Step 5: Solve for x
    x = 17,733.80/145.48
  6. Step 6: Final answer
    x = 121.90

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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.