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Finding the Fourth Proportional to 91.02, 136.49 and 56.78

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Solution

The fourth proportional to 91.02, 136.49 and 56.78 is: 85.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.02 : 136.49 = 56.78 : x
  2. Step 2: Convert to fraction form
    91.02/136.49 = 56.78/x
  3. Step 3: Cross multiply
    91.02x = 136.49 × 56.78
  4. Step 4: Simplify right side
    91.02x = 7,749.90
  5. Step 5: Solve for x
    x = 7,749.90/91.02
  6. Step 6: Final answer
    x = 85.15

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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.