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Finding the Fourth Proportional to 654.80, 979.80 and 438.80

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Solution

The fourth proportional to 654.80, 979.80 and 438.80 is: 656.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    654.80 : 979.80 = 438.80 : x
  2. Step 2: Convert to fraction form
    654.80/979.80 = 438.80/x
  3. Step 3: Cross multiply
    654.80x = 979.80 × 438.80
  4. Step 4: Simplify right side
    654.80x = 429,936.24
  5. Step 5: Solve for x
    x = 429,936.24/654.80
  6. Step 6: Final answer
    x = 656.59

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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.