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Finding the Fourth Proportional to 427.72, 590.90 and 287.80

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Solution

The fourth proportional to 427.72, 590.90 and 287.80 is: 397.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.72 : 590.90 = 287.80 : x
  2. Step 2: Convert to fraction form
    427.72/590.90 = 287.80/x
  3. Step 3: Cross multiply
    427.72x = 590.90 × 287.80
  4. Step 4: Simplify right side
    427.72x = 170,061.02
  5. Step 5: Solve for x
    x = 170,061.02/427.72
  6. Step 6: Final answer
    x = 397.60

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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.