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Finding the Fourth Proportional to 400.80, 601.20 and 208.40

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Solution

The fourth proportional to 400.80, 601.20 and 208.40 is: 312.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    400.80 : 601.20 = 208.40 : x
  2. Step 2: Convert to fraction form
    400.80/601.20 = 208.40/x
  3. Step 3: Cross multiply
    400.80x = 601.20 × 208.40
  4. Step 4: Simplify right side
    400.80x = 125,290.08
  5. Step 5: Solve for x
    x = 125,290.08/400.80
  6. Step 6: Final answer
    x = 312.60

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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.