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Finding the Fourth Proportional to 91.20, 125.78 and 70.45

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Solution

The fourth proportional to 91.20, 125.78 and 70.45 is: 97.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.20 : 125.78 = 70.45 : x
  2. Step 2: Convert to fraction form
    91.20/125.78 = 70.45/x
  3. Step 3: Cross multiply
    91.20x = 125.78 × 70.45
  4. Step 4: Simplify right side
    91.20x = 8,861.20
  5. Step 5: Solve for x
    x = 8,861.20/91.20
  6. Step 6: Final answer
    x = 97.16

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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.