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Finding the Fourth Proportional to 72.90, 108.72 and 71.46

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Solution

The fourth proportional to 72.90, 108.72 and 71.46 is: 106.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.90 : 108.72 = 71.46 : x
  2. Step 2: Convert to fraction form
    72.90/108.72 = 71.46/x
  3. Step 3: Cross multiply
    72.90x = 108.72 × 71.46
  4. Step 4: Simplify right side
    72.90x = 7,769.13
  5. Step 5: Solve for x
    x = 7,769.13/72.90
  6. Step 6: Final answer
    x = 106.57

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.