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Finding the Fourth Proportional to 137.70, 189.80 and 100.85

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Solution

The fourth proportional to 137.70, 189.80 and 100.85 is: 139.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.70 : 189.80 = 100.85 : x
  2. Step 2: Convert to fraction form
    137.70/189.80 = 100.85/x
  3. Step 3: Cross multiply
    137.70x = 189.80 × 100.85
  4. Step 4: Simplify right side
    137.70x = 19,141.34
  5. Step 5: Solve for x
    x = 19,141.34/137.70
  6. Step 6: Final answer
    x = 139.00

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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.