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Finding the Fourth Proportional to 140.30, 210.65 and 128.15

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Solution

The fourth proportional to 140.30, 210.65 and 128.15 is: 192.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.30 : 210.65 = 128.15 : x
  2. Step 2: Convert to fraction form
    140.30/210.65 = 128.15/x
  3. Step 3: Cross multiply
    140.30x = 210.65 × 128.15
  4. Step 4: Simplify right side
    140.30x = 26,993.10
  5. Step 5: Solve for x
    x = 26,993.10/140.30
  6. Step 6: Final answer
    x = 192.40

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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.