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Finding the Fourth Proportional to 145.43, 218.15 and 81.71

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Solution

The fourth proportional to 145.43, 218.15 and 81.71 is: 122.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.43 : 218.15 = 81.71 : x
  2. Step 2: Convert to fraction form
    145.43/218.15 = 81.71/x
  3. Step 3: Cross multiply
    145.43x = 218.15 × 81.71
  4. Step 4: Simplify right side
    145.43x = 17,825.04
  5. Step 5: Solve for x
    x = 17,825.04/145.43
  6. Step 6: Final answer
    x = 122.57

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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.