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Finding the Fourth Proportional to 77.30, 115.95 and 31.65

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Solution

The fourth proportional to 77.30, 115.95 and 31.65 is: 47.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.30 : 115.95 = 31.65 : x
  2. Step 2: Convert to fraction form
    77.30/115.95 = 31.65/x
  3. Step 3: Cross multiply
    77.30x = 115.95 × 31.65
  4. Step 4: Simplify right side
    77.30x = 3,669.82
  5. Step 5: Solve for x
    x = 3,669.82/77.30
  6. Step 6: Final answer
    x = 47.48

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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.