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Finding the Fourth Proportional to 212.16, 318.24 and 142.78

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Solution

The fourth proportional to 212.16, 318.24 and 142.78 is: 214.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.16 : 318.24 = 142.78 : x
  2. Step 2: Convert to fraction form
    212.16/318.24 = 142.78/x
  3. Step 3: Cross multiply
    212.16x = 318.24 × 142.78
  4. Step 4: Simplify right side
    212.16x = 45,438.31
  5. Step 5: Solve for x
    x = 45,438.31/212.16
  6. Step 6: Final answer
    x = 214.17

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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.