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Finding the Fourth Proportional to 766.21, 1,056.90 and 668.20

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Solution

The fourth proportional to 766.21, 1,056.90 and 668.20 is: 921.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    766.21 : 1,056.90 = 668.20 : x
  2. Step 2: Convert to fraction form
    766.21/1,056.90 = 668.20/x
  3. Step 3: Cross multiply
    766.21x = 1,056.90 × 668.20
  4. Step 4: Simplify right side
    766.21x = 706,220.58
  5. Step 5: Solve for x
    x = 706,220.58/766.21
  6. Step 6: Final answer
    x = 921.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.