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Finding the Fourth Proportional to 98.68, 147.80 and 76.90

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Solution

The fourth proportional to 98.68, 147.80 and 76.90 is: 115.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.68 : 147.80 = 76.90 : x
  2. Step 2: Convert to fraction form
    98.68/147.80 = 76.90/x
  3. Step 3: Cross multiply
    98.68x = 147.80 × 76.90
  4. Step 4: Simplify right side
    98.68x = 11,365.82
  5. Step 5: Solve for x
    x = 11,365.82/98.68
  6. Step 6: Final answer
    x = 115.18

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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.