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Finding the Fourth Proportional to 98.61, 135.99 and 87.81

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Solution

The fourth proportional to 98.61, 135.99 and 87.81 is: 121.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.61 : 135.99 = 87.81 : x
  2. Step 2: Convert to fraction form
    98.61/135.99 = 87.81/x
  3. Step 3: Cross multiply
    98.61x = 135.99 × 87.81
  4. Step 4: Simplify right side
    98.61x = 11,941.28
  5. Step 5: Solve for x
    x = 11,941.28/98.61
  6. Step 6: Final answer
    x = 121.10

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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.