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Finding the Fourth Proportional to 253.86, 380.70 and 71.21

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Solution

The fourth proportional to 253.86, 380.70 and 71.21 is: 106.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    253.86 : 380.70 = 71.21 : x
  2. Step 2: Convert to fraction form
    253.86/380.70 = 71.21/x
  3. Step 3: Cross multiply
    253.86x = 380.70 × 71.21
  4. Step 4: Simplify right side
    253.86x = 27,110.02
  5. Step 5: Solve for x
    x = 27,110.02/253.86
  6. Step 6: Final answer
    x = 106.79

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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.