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Finding the Fourth Proportional to 253.86, 380.78 and 99.81

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Solution

The fourth proportional to 253.86, 380.78 and 99.81 is: 149.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    253.86 : 380.78 = 99.81 : x
  2. Step 2: Convert to fraction form
    253.86/380.78 = 99.81/x
  3. Step 3: Cross multiply
    253.86x = 380.78 × 99.81
  4. Step 4: Simplify right side
    253.86x = 38,005.65
  5. Step 5: Solve for x
    x = 38,005.65/253.86
  6. Step 6: Final answer
    x = 149.71

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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.