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Finding the Fourth Proportional to 388.64, 582.86 and 128.66

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Solution

The fourth proportional to 388.64, 582.86 and 128.66 is: 192.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.64 : 582.86 = 128.66 : x
  2. Step 2: Convert to fraction form
    388.64/582.86 = 128.66/x
  3. Step 3: Cross multiply
    388.64x = 582.86 × 128.66
  4. Step 4: Simplify right side
    388.64x = 74,990.77
  5. Step 5: Solve for x
    x = 74,990.77/388.64
  6. Step 6: Final answer
    x = 192.96

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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.