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Finding the Fourth Proportional to 98.78, 147.60 and 80.69

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Solution

The fourth proportional to 98.78, 147.60 and 80.69 is: 120.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.78 : 147.60 = 80.69 : x
  2. Step 2: Convert to fraction form
    98.78/147.60 = 80.69/x
  3. Step 3: Cross multiply
    98.78x = 147.60 × 80.69
  4. Step 4: Simplify right side
    98.78x = 11,909.11
  5. Step 5: Solve for x
    x = 11,909.11/98.78
  6. Step 6: Final answer
    x = 120.57

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.