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Finding the Fourth Proportional to 91.90, 137.70 and 57.58

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Solution

The fourth proportional to 91.90, 137.70 and 57.58 is: 86.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.90 : 137.70 = 57.58 : x
  2. Step 2: Convert to fraction form
    91.90/137.70 = 57.58/x
  3. Step 3: Cross multiply
    91.90x = 137.70 × 57.58
  4. Step 4: Simplify right side
    91.90x = 7,928.77
  5. Step 5: Solve for x
    x = 7,928.77/91.90
  6. Step 6: Final answer
    x = 86.28

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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.