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Finding the Fourth Proportional to 82.80, 124.29 and 42.21

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Solution

The fourth proportional to 82.80, 124.29 and 42.21 is: 63.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.80 : 124.29 = 42.21 : x
  2. Step 2: Convert to fraction form
    82.80/124.29 = 42.21/x
  3. Step 3: Cross multiply
    82.80x = 124.29 × 42.21
  4. Step 4: Simplify right side
    82.80x = 5,246.28
  5. Step 5: Solve for x
    x = 5,246.28/82.80
  6. Step 6: Final answer
    x = 63.36

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.