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Finding the Fourth Proportional to 137.56, 189.74 and 85.72

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Solution

The fourth proportional to 137.56, 189.74 and 85.72 is: 118.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.56 : 189.74 = 85.72 : x
  2. Step 2: Convert to fraction form
    137.56/189.74 = 85.72/x
  3. Step 3: Cross multiply
    137.56x = 189.74 × 85.72
  4. Step 4: Simplify right side
    137.56x = 16,264.51
  5. Step 5: Solve for x
    x = 16,264.51/137.56
  6. Step 6: Final answer
    x = 118.24

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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.