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Finding the Fourth Proportional to 385.48, 578.16 and 128.98

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Solution

The fourth proportional to 385.48, 578.16 and 128.98 is: 193.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.48 : 578.16 = 128.98 : x
  2. Step 2: Convert to fraction form
    385.48/578.16 = 128.98/x
  3. Step 3: Cross multiply
    385.48x = 578.16 × 128.98
  4. Step 4: Simplify right side
    385.48x = 74,571.08
  5. Step 5: Solve for x
    x = 74,571.08/385.48
  6. Step 6: Final answer
    x = 193.45

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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.