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Finding the Fourth Proportional to 425.80, 639 and 317.80

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Solution

The fourth proportional to 425.80, 639 and 317.80 is: 476.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.80 : 639 = 317.80 : x
  2. Step 2: Convert to fraction form
    425.80/639 = 317.80/x
  3. Step 3: Cross multiply
    425.80x = 639 × 317.80
  4. Step 4: Simplify right side
    425.80x = 203,074.20
  5. Step 5: Solve for x
    x = 203,074.20/425.80
  6. Step 6: Final answer
    x = 476.92

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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.