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Finding the Fourth Proportional to 405.80, 559.40 and 287.60

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Solution

The fourth proportional to 405.80, 559.40 and 287.60 is: 396.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.80 : 559.40 = 287.60 : x
  2. Step 2: Convert to fraction form
    405.80/559.40 = 287.60/x
  3. Step 3: Cross multiply
    405.80x = 559.40 × 287.60
  4. Step 4: Simplify right side
    405.80x = 160,883.44
  5. Step 5: Solve for x
    x = 160,883.44/405.80
  6. Step 6: Final answer
    x = 396.46

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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.