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Finding the Fourth Proportional to 136.70, 188.72 and 90.15

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Solution

The fourth proportional to 136.70, 188.72 and 90.15 is: 124.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.70 : 188.72 = 90.15 : x
  2. Step 2: Convert to fraction form
    136.70/188.72 = 90.15/x
  3. Step 3: Cross multiply
    136.70x = 188.72 × 90.15
  4. Step 4: Simplify right side
    136.70x = 17,013.11
  5. Step 5: Solve for x
    x = 17,013.11/136.70
  6. Step 6: Final answer
    x = 124.46

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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.