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Finding the Fourth Proportional to 998.30, 1,377.32 and 666.78

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Solution

The fourth proportional to 998.30, 1,377.32 and 666.78 is: 919.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.30 : 1,377.32 = 666.78 : x
  2. Step 2: Convert to fraction form
    998.30/1,377.32 = 666.78/x
  3. Step 3: Cross multiply
    998.30x = 1,377.32 × 666.78
  4. Step 4: Simplify right side
    998.30x = 918,369.43
  5. Step 5: Solve for x
    x = 918,369.43/998.30
  6. Step 6: Final answer
    x = 919.93

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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.