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Finding the Fourth Proportional to 98.87, 136.61 and 78.30

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Solution

The fourth proportional to 98.87, 136.61 and 78.30 is: 108.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.87 : 136.61 = 78.30 : x
  2. Step 2: Convert to fraction form
    98.87/136.61 = 78.30/x
  3. Step 3: Cross multiply
    98.87x = 136.61 × 78.30
  4. Step 4: Simplify right side
    98.87x = 10,696.17
  5. Step 5: Solve for x
    x = 10,696.17/98.87
  6. Step 6: Final answer
    x = 108.19

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.