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Finding the Fourth Proportional to 142.16, 212.15 and 138.51

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Solution

The fourth proportional to 142.16, 212.15 and 138.51 is: 206.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.16 : 212.15 = 138.51 : x
  2. Step 2: Convert to fraction form
    142.16/212.15 = 138.51/x
  3. Step 3: Cross multiply
    142.16x = 212.15 × 138.51
  4. Step 4: Simplify right side
    142.16x = 29,384.90
  5. Step 5: Solve for x
    x = 29,384.90/142.16
  6. Step 6: Final answer
    x = 206.71

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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.