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Finding the Fourth Proportional to 428.01, 642.60 and 265.20

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Solution

The fourth proportional to 428.01, 642.60 and 265.20 is: 398.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.01 : 642.60 = 265.20 : x
  2. Step 2: Convert to fraction form
    428.01/642.60 = 265.20/x
  3. Step 3: Cross multiply
    428.01x = 642.60 × 265.20
  4. Step 4: Simplify right side
    428.01x = 170,417.52
  5. Step 5: Solve for x
    x = 170,417.52/428.01
  6. Step 6: Final answer
    x = 398.16

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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.