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Finding the Fourth Proportional to 51.86, 77.76 and 19.80

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Solution

The fourth proportional to 51.86, 77.76 and 19.80 is: 29.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.86 : 77.76 = 19.80 : x
  2. Step 2: Convert to fraction form
    51.86/77.76 = 19.80/x
  3. Step 3: Cross multiply
    51.86x = 77.76 × 19.80
  4. Step 4: Simplify right side
    51.86x = 1,539.65
  5. Step 5: Solve for x
    x = 1,539.65/51.86
  6. Step 6: Final answer
    x = 29.69

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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.