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Finding the Fourth Proportional to 387.30, 580.70 and 127.20

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Solution

The fourth proportional to 387.30, 580.70 and 127.20 is: 190.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.30 : 580.70 = 127.20 : x
  2. Step 2: Convert to fraction form
    387.30/580.70 = 127.20/x
  3. Step 3: Cross multiply
    387.30x = 580.70 × 127.20
  4. Step 4: Simplify right side
    387.30x = 73,865.04
  5. Step 5: Solve for x
    x = 73,865.04/387.30
  6. Step 6: Final answer
    x = 190.72

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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.