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Finding the Fourth Proportional to 142.86, 214.40 and 77.90

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Solution

The fourth proportional to 142.86, 214.40 and 77.90 is: 116.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.86 : 214.40 = 77.90 : x
  2. Step 2: Convert to fraction form
    142.86/214.40 = 77.90/x
  3. Step 3: Cross multiply
    142.86x = 214.40 × 77.90
  4. Step 4: Simplify right side
    142.86x = 16,701.76
  5. Step 5: Solve for x
    x = 16,701.76/142.86
  6. Step 6: Final answer
    x = 116.91

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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.