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Finding the Fourth Proportional to 212.19, 292.86 and 138.72

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Solution

The fourth proportional to 212.19, 292.86 and 138.72 is: 191.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.19 : 292.86 = 138.72 : x
  2. Step 2: Convert to fraction form
    212.19/292.86 = 138.72/x
  3. Step 3: Cross multiply
    212.19x = 292.86 × 138.72
  4. Step 4: Simplify right side
    212.19x = 40,625.54
  5. Step 5: Solve for x
    x = 40,625.54/212.19
  6. Step 6: Final answer
    x = 191.46

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.