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Finding the Fourth Proportional to 809.60, 1,214.40 and 665.60

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Solution

The fourth proportional to 809.60, 1,214.40 and 665.60 is: 998.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.60 : 1,214.40 = 665.60 : x
  2. Step 2: Convert to fraction form
    809.60/1,214.40 = 665.60/x
  3. Step 3: Cross multiply
    809.60x = 1,214.40 × 665.60
  4. Step 4: Simplify right side
    809.60x = 808,304.64
  5. Step 5: Solve for x
    x = 808,304.64/809.60
  6. Step 6: Final answer
    x = 998.40

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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.