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Finding the Fourth Proportional to 666.78, 919.98 and 427.59

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Solution

The fourth proportional to 666.78, 919.98 and 427.59 is: 589.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.78 : 919.98 = 427.59 : x
  2. Step 2: Convert to fraction form
    666.78/919.98 = 427.59/x
  3. Step 3: Cross multiply
    666.78x = 919.98 × 427.59
  4. Step 4: Simplify right side
    666.78x = 393,374.25
  5. Step 5: Solve for x
    x = 393,374.25/666.78
  6. Step 6: Final answer
    x = 589.96

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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.