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Finding the Fourth Proportional to 210.30, 315.12 and 128.97

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Solution

The fourth proportional to 210.30, 315.12 and 128.97 is: 193.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.30 : 315.12 = 128.97 : x
  2. Step 2: Convert to fraction form
    210.30/315.12 = 128.97/x
  3. Step 3: Cross multiply
    210.30x = 315.12 × 128.97
  4. Step 4: Simplify right side
    210.30x = 40,641.03
  5. Step 5: Solve for x
    x = 40,641.03/210.30
  6. Step 6: Final answer
    x = 193.25

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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.