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Finding the Fourth Proportional to 136.98, 189.15 and 87.99

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Solution

The fourth proportional to 136.98, 189.15 and 87.99 is: 121.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.98 : 189.15 = 87.99 : x
  2. Step 2: Convert to fraction form
    136.98/189.15 = 87.99/x
  3. Step 3: Cross multiply
    136.98x = 189.15 × 87.99
  4. Step 4: Simplify right side
    136.98x = 16,643.31
  5. Step 5: Solve for x
    x = 16,643.31/136.98
  6. Step 6: Final answer
    x = 121.50

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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.