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Finding the Fourth Proportional to 142.76, 214.08 and 78.56

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Solution

The fourth proportional to 142.76, 214.08 and 78.56 is: 117.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.76 : 214.08 = 78.56 : x
  2. Step 2: Convert to fraction form
    142.76/214.08 = 78.56/x
  3. Step 3: Cross multiply
    142.76x = 214.08 × 78.56
  4. Step 4: Simplify right side
    142.76x = 16,818.12
  5. Step 5: Solve for x
    x = 16,818.12/142.76
  6. Step 6: Final answer
    x = 117.81

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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.