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Finding the Fourth Proportional to 137.40, 206.15 and 72.45

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Solution

The fourth proportional to 137.40, 206.15 and 72.45 is: 108.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.40 : 206.15 = 72.45 : x
  2. Step 2: Convert to fraction form
    137.40/206.15 = 72.45/x
  3. Step 3: Cross multiply
    137.40x = 206.15 × 72.45
  4. Step 4: Simplify right side
    137.40x = 14,935.57
  5. Step 5: Solve for x
    x = 14,935.57/137.40
  6. Step 6: Final answer
    x = 108.70

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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.