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Finding the Fourth Proportional to 638, 955 and 407.15

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Solution

The fourth proportional to 638, 955 and 407.15 is: 609.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    638 : 955 = 407.15 : x
  2. Step 2: Convert to fraction form
    638/955 = 407.15/x
  3. Step 3: Cross multiply
    638x = 955 × 407.15
  4. Step 4: Simplify right side
    638x = 388,828.25
  5. Step 5: Solve for x
    x = 388,828.25/638
  6. Step 6: Final answer
    x = 609.45

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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.