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Finding the Fourth Proportional to 1,217.90, 1,823.60 and 639.56

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Solution

The fourth proportional to 1,217.90, 1,823.60 and 639.56 is: 957.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,217.90 : 1,823.60 = 639.56 : x
  2. Step 2: Convert to fraction form
    1,217.90/1,823.60 = 639.56/x
  3. Step 3: Cross multiply
    1,217.90x = 1,823.60 × 639.56
  4. Step 4: Simplify right side
    1,217.90x = 1,166,301.62
  5. Step 5: Solve for x
    x = 1,166,301.62/1,217.90
  6. Step 6: Final answer
    x = 957.63

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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.