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Finding the Fourth Proportional to 927.90, 1,390.80 and 379.78

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Solution

The fourth proportional to 927.90, 1,390.80 and 379.78 is: 569.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    927.90 : 1,390.80 = 379.78 : x
  2. Step 2: Convert to fraction form
    927.90/1,390.80 = 379.78/x
  3. Step 3: Cross multiply
    927.90x = 1,390.80 × 379.78
  4. Step 4: Simplify right side
    927.90x = 528,197.07
  5. Step 5: Solve for x
    x = 528,197.07/927.90
  6. Step 6: Final answer
    x = 569.24

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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.