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Finding the Fourth Proportional to 91.28, 126.85 and 90.35

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Solution

The fourth proportional to 91.28, 126.85 and 90.35 is: 125.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.28 : 126.85 = 90.35 : x
  2. Step 2: Convert to fraction form
    91.28/126.85 = 90.35/x
  3. Step 3: Cross multiply
    91.28x = 126.85 × 90.35
  4. Step 4: Simplify right side
    91.28x = 11,459.81
  5. Step 5: Solve for x
    x = 11,459.81/91.28
  6. Step 6: Final answer
    x = 125.54

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.