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Finding the Fourth Proportional to 74.65, 102.90 and 72.70

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Solution

The fourth proportional to 74.65, 102.90 and 72.70 is: 100.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.65 : 102.90 = 72.70 : x
  2. Step 2: Convert to fraction form
    74.65/102.90 = 72.70/x
  3. Step 3: Cross multiply
    74.65x = 102.90 × 72.70
  4. Step 4: Simplify right side
    74.65x = 7,480.83
  5. Step 5: Solve for x
    x = 7,480.83/74.65
  6. Step 6: Final answer
    x = 100.21

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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.