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Finding the Fourth Proportional to 103.76, 155.84 and 76.80

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Solution

The fourth proportional to 103.76, 155.84 and 76.80 is: 115.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.76 : 155.84 = 76.80 : x
  2. Step 2: Convert to fraction form
    103.76/155.84 = 76.80/x
  3. Step 3: Cross multiply
    103.76x = 155.84 × 76.80
  4. Step 4: Simplify right side
    103.76x = 11,968.51
  5. Step 5: Solve for x
    x = 11,968.51/103.76
  6. Step 6: Final answer
    x = 115.35

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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.