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Finding the Fourth Proportional to 140.68, 210.50 and 85.64

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Solution

The fourth proportional to 140.68, 210.50 and 85.64 is: 128.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.68 : 210.50 = 85.64 : x
  2. Step 2: Convert to fraction form
    140.68/210.50 = 85.64/x
  3. Step 3: Cross multiply
    140.68x = 210.50 × 85.64
  4. Step 4: Simplify right side
    140.68x = 18,027.22
  5. Step 5: Solve for x
    x = 18,027.22/140.68
  6. Step 6: Final answer
    x = 128.14

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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.