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Finding the Fourth Proportional to 638.12, 957.18 and 421.65

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Solution

The fourth proportional to 638.12, 957.18 and 421.65 is: 632.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.12 : 957.18 = 421.65 : x
  2. Step 2: Convert to fraction form
    638.12/957.18 = 421.65/x
  3. Step 3: Cross multiply
    638.12x = 957.18 × 421.65
  4. Step 4: Simplify right side
    638.12x = 403,594.95
  5. Step 5: Solve for x
    x = 403,594.95/638.12
  6. Step 6: Final answer
    x = 632.47

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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.