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Finding the Fourth Proportional to 85.76, 128.55 and 49.62

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Solution

The fourth proportional to 85.76, 128.55 and 49.62 is: 74.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.76 : 128.55 = 49.62 : x
  2. Step 2: Convert to fraction form
    85.76/128.55 = 49.62/x
  3. Step 3: Cross multiply
    85.76x = 128.55 × 49.62
  4. Step 4: Simplify right side
    85.76x = 6,378.65
  5. Step 5: Solve for x
    x = 6,378.65/85.76
  6. Step 6: Final answer
    x = 74.38

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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.