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Finding the Fourth Proportional to 455.42, 680.00 and 390.32

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Solution

The fourth proportional to 455.42, 680.00 and 390.32 is: 582.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.42 : 680.00 = 390.32 : x
  2. Step 2: Convert to fraction form
    455.42/680.00 = 390.32/x
  3. Step 3: Cross multiply
    455.42x = 680.00 × 390.32
  4. Step 4: Simplify right side
    455.42x = 265,414.80
  5. Step 5: Solve for x
    x = 265,414.80/455.42
  6. Step 6: Final answer
    x = 582.79

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.