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Finding the Fourth Proportional to 143.76, 214.80 and 138.72

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Solution

The fourth proportional to 143.76, 214.80 and 138.72 is: 207.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.76 : 214.80 = 138.72 : x
  2. Step 2: Convert to fraction form
    143.76/214.80 = 138.72/x
  3. Step 3: Cross multiply
    143.76x = 214.80 × 138.72
  4. Step 4: Simplify right side
    143.76x = 29,797.06
  5. Step 5: Solve for x
    x = 29,797.06/143.76
  6. Step 6: Final answer
    x = 207.27

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.