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Finding the Fourth Proportional to 72.40, 109.11 and 65.55

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Solution

The fourth proportional to 72.40, 109.11 and 65.55 is: 98.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.40 : 109.11 = 65.55 : x
  2. Step 2: Convert to fraction form
    72.40/109.11 = 65.55/x
  3. Step 3: Cross multiply
    72.40x = 109.11 × 65.55
  4. Step 4: Simplify right side
    72.40x = 7,152.16
  5. Step 5: Solve for x
    x = 7,152.16/72.40
  6. Step 6: Final answer
    x = 98.79

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.