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Finding the Fourth Proportional to 138.02, 206.85 and 56.75

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Solution

The fourth proportional to 138.02, 206.85 and 56.75 is: 85.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.02 : 206.85 = 56.75 : x
  2. Step 2: Convert to fraction form
    138.02/206.85 = 56.75/x
  3. Step 3: Cross multiply
    138.02x = 206.85 × 56.75
  4. Step 4: Simplify right side
    138.02x = 11,738.74
  5. Step 5: Solve for x
    x = 11,738.74/138.02
  6. Step 6: Final answer
    x = 85.05

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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.