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Finding the Fourth Proportional to 243.90, 365.68 and 128.20

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Solution

The fourth proportional to 243.90, 365.68 and 128.20 is: 192.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    243.90 : 365.68 = 128.20 : x
  2. Step 2: Convert to fraction form
    243.90/365.68 = 128.20/x
  3. Step 3: Cross multiply
    243.90x = 365.68 × 128.20
  4. Step 4: Simplify right side
    243.90x = 46,880.18
  5. Step 5: Solve for x
    x = 46,880.18/243.90
  6. Step 6: Final answer
    x = 192.21

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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.