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Finding the Fourth Proportional to 72.71, 100.20 and 57.91

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Solution

The fourth proportional to 72.71, 100.20 and 57.91 is: 79.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.71 : 100.20 = 57.91 : x
  2. Step 2: Convert to fraction form
    72.71/100.20 = 57.91/x
  3. Step 3: Cross multiply
    72.71x = 100.20 × 57.91
  4. Step 4: Simplify right side
    72.71x = 5,802.11
  5. Step 5: Solve for x
    x = 5,802.11/72.71
  6. Step 6: Final answer
    x = 79.80

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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.