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Finding the Fourth Proportional to 812.60, 1,218.90 and 666.80

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Solution

The fourth proportional to 812.60, 1,218.90 and 666.80 is: 1,000.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.60 : 1,218.90 = 666.80 : x
  2. Step 2: Convert to fraction form
    812.60/1,218.90 = 666.80/x
  3. Step 3: Cross multiply
    812.60x = 1,218.90 × 666.80
  4. Step 4: Simplify right side
    812.60x = 812,762.52
  5. Step 5: Solve for x
    x = 812,762.52/812.60
  6. Step 6: Final answer
    x = 1,000.20

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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.