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Finding the Fourth Proportional to 115.47, 159.35 and 71.78

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Solution

The fourth proportional to 115.47, 159.35 and 71.78 is: 99.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.47 : 159.35 = 71.78 : x
  2. Step 2: Convert to fraction form
    115.47/159.35 = 71.78/x
  3. Step 3: Cross multiply
    115.47x = 159.35 × 71.78
  4. Step 4: Simplify right side
    115.47x = 11,436.99
  5. Step 5: Solve for x
    x = 11,436.99/115.47
  6. Step 6: Final answer
    x = 99.05

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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.