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Finding the Fourth Proportional to 49.85, 74.78 and 13.78

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Solution

The fourth proportional to 49.85, 74.78 and 13.78 is: 20.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    49.85 : 74.78 = 13.78 : x
  2. Step 2: Convert to fraction form
    49.85/74.78 = 13.78/x
  3. Step 3: Cross multiply
    49.85x = 74.78 × 13.78
  4. Step 4: Simplify right side
    49.85x = 1,030.66
  5. Step 5: Solve for x
    x = 1,030.66/49.85
  6. Step 6: Final answer
    x = 20.67

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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.