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Finding the Fourth Proportional to 666.90, 998.80 and 643.83

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Solution

The fourth proportional to 666.90, 998.80 and 643.83 is: 964.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.90 : 998.80 = 643.83 : x
  2. Step 2: Convert to fraction form
    666.90/998.80 = 643.83/x
  3. Step 3: Cross multiply
    666.90x = 998.80 × 643.83
  4. Step 4: Simplify right side
    666.90x = 643,057.40
  5. Step 5: Solve for x
    x = 643,057.40/666.90
  6. Step 6: Final answer
    x = 964.25

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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.