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Finding the Fourth Proportional to 387.70, 581.60 and 127.80

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Solution

The fourth proportional to 387.70, 581.60 and 127.80 is: 191.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.70 : 581.60 = 127.80 : x
  2. Step 2: Convert to fraction form
    387.70/581.60 = 127.80/x
  3. Step 3: Cross multiply
    387.70x = 581.60 × 127.80
  4. Step 4: Simplify right side
    387.70x = 74,328.48
  5. Step 5: Solve for x
    x = 74,328.48/387.70
  6. Step 6: Final answer
    x = 191.72

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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.