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Finding the Fourth Proportional to 275.12, 412.40 and 128.91

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Solution

The fourth proportional to 275.12, 412.40 and 128.91 is: 193.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    275.12 : 412.40 = 128.91 : x
  2. Step 2: Convert to fraction form
    275.12/412.40 = 128.91/x
  3. Step 3: Cross multiply
    275.12x = 412.40 × 128.91
  4. Step 4: Simplify right side
    275.12x = 53,161.84
  5. Step 5: Solve for x
    x = 53,161.84/275.12
  6. Step 6: Final answer
    x = 193.23

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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.