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Finding the Fourth Proportional to 1,281.21, 1,920.25 and 664.58

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Solution

The fourth proportional to 1,281.21, 1,920.25 and 664.58 is: 996.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.21 : 1,920.25 = 664.58 : x
  2. Step 2: Convert to fraction form
    1,281.21/1,920.25 = 664.58/x
  3. Step 3: Cross multiply
    1,281.21x = 1,920.25 × 664.58
  4. Step 4: Simplify right side
    1,281.21x = 1,276,159.75
  5. Step 5: Solve for x
    x = 1,276,159.75/1,281.21
  6. Step 6: Final answer
    x = 996.06

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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.