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Finding the Fourth Proportional to 151.72, 209.40 and 115

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Solution

The fourth proportional to 151.72, 209.40 and 115 is: 158.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.72 : 209.40 = 115 : x
  2. Step 2: Convert to fraction form
    151.72/209.40 = 115/x
  3. Step 3: Cross multiply
    151.72x = 209.40 × 115
  4. Step 4: Simplify right side
    151.72x = 24,081
  5. Step 5: Solve for x
    x = 24,081/151.72
  6. Step 6: Final answer
    x = 158.72

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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.