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Finding the Fourth Proportional to 140.21, 210.36 and 71.72

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Solution

The fourth proportional to 140.21, 210.36 and 71.72 is: 107.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.21 : 210.36 = 71.72 : x
  2. Step 2: Convert to fraction form
    140.21/210.36 = 71.72/x
  3. Step 3: Cross multiply
    140.21x = 210.36 × 71.72
  4. Step 4: Simplify right side
    140.21x = 15,087.02
  5. Step 5: Solve for x
    x = 15,087.02/140.21
  6. Step 6: Final answer
    x = 107.60

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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.