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Finding the Fourth Proportional to 71.74, 99.00 and 39.00

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Solution

The fourth proportional to 71.74, 99.00 and 39.00 is: 53.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.74 : 99.00 = 39.00 : x
  2. Step 2: Convert to fraction form
    71.74/99.00 = 39.00/x
  3. Step 3: Cross multiply
    71.74x = 99.00 × 39.00
  4. Step 4: Simplify right side
    71.74x = 3,860.72
  5. Step 5: Solve for x
    x = 3,860.72/71.74
  6. Step 6: Final answer
    x = 53.81

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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.