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Finding the Fourth Proportional to 71.72, 106.80 and 71.40

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Solution

The fourth proportional to 71.72, 106.80 and 71.40 is: 106.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.72 : 106.80 = 71.40 : x
  2. Step 2: Convert to fraction form
    71.72/106.80 = 71.40/x
  3. Step 3: Cross multiply
    71.72x = 106.80 × 71.40
  4. Step 4: Simplify right side
    71.72x = 7,625.52
  5. Step 5: Solve for x
    x = 7,625.52/71.72
  6. Step 6: Final answer
    x = 106.32

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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.