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Finding the Fourth Proportional to 71.89, 99.21 and 40.79

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Solution

The fourth proportional to 71.89, 99.21 and 40.79 is: 56.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.89 : 99.21 = 40.79 : x
  2. Step 2: Convert to fraction form
    71.89/99.21 = 40.79/x
  3. Step 3: Cross multiply
    71.89x = 99.21 × 40.79
  4. Step 4: Simplify right side
    71.89x = 4,047.02
  5. Step 5: Solve for x
    x = 4,047.02/71.89
  6. Step 6: Final answer
    x = 56.30

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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.