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Finding the Fourth Proportional to 386.78, 580.16 and 98.21

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Solution

The fourth proportional to 386.78, 580.16 and 98.21 is: 147.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.78 : 580.16 = 98.21 : x
  2. Step 2: Convert to fraction form
    386.78/580.16 = 98.21/x
  3. Step 3: Cross multiply
    386.78x = 580.16 × 98.21
  4. Step 4: Simplify right side
    386.78x = 56,977.02
  5. Step 5: Solve for x
    x = 56,977.02/386.78
  6. Step 6: Final answer
    x = 147.31

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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.