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Finding the Fourth Proportional to 253.89, 380.75 and 99.78

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Solution

The fourth proportional to 253.89, 380.75 and 99.78 is: 149.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    253.89 : 380.75 = 99.78 : x
  2. Step 2: Convert to fraction form
    253.89/380.75 = 99.78/x
  3. Step 3: Cross multiply
    253.89x = 380.75 × 99.78
  4. Step 4: Simplify right side
    253.89x = 37,991.24
  5. Step 5: Solve for x
    x = 37,991.24/253.89
  6. Step 6: Final answer
    x = 149.64

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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.