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Finding the Fourth Proportional to 82.90, 123.80 and 71.52

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Solution

The fourth proportional to 82.90, 123.80 and 71.52 is: 106.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.90 : 123.80 = 71.52 : x
  2. Step 2: Convert to fraction form
    82.90/123.80 = 71.52/x
  3. Step 3: Cross multiply
    82.90x = 123.80 × 71.52
  4. Step 4: Simplify right side
    82.90x = 8,854.18
  5. Step 5: Solve for x
    x = 8,854.18/82.90
  6. Step 6: Final answer
    x = 106.81

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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.