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Finding the Fourth Proportional to 103.90, 155.86 and 49.78

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Solution

The fourth proportional to 103.90, 155.86 and 49.78 is: 74.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.90 : 155.86 = 49.78 : x
  2. Step 2: Convert to fraction form
    103.90/155.86 = 49.78/x
  3. Step 3: Cross multiply
    103.90x = 155.86 × 49.78
  4. Step 4: Simplify right side
    103.90x = 7,758.71
  5. Step 5: Solve for x
    x = 7,758.71/103.90
  6. Step 6: Final answer
    x = 74.67

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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.