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Finding the Fourth Proportional to 811.32, 1,217.70 and 648.60

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Solution

The fourth proportional to 811.32, 1,217.70 and 648.60 is: 973.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.32 : 1,217.70 = 648.60 : x
  2. Step 2: Convert to fraction form
    811.32/1,217.70 = 648.60/x
  3. Step 3: Cross multiply
    811.32x = 1,217.70 × 648.60
  4. Step 4: Simplify right side
    811.32x = 789,800.22
  5. Step 5: Solve for x
    x = 789,800.22/811.32
  6. Step 6: Final answer
    x = 973.48

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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.