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Finding the Fourth Proportional to 401.60, 603.30 and 390.80

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Solution

The fourth proportional to 401.60, 603.30 and 390.80 is: 587.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    401.60 : 603.30 = 390.80 : x
  2. Step 2: Convert to fraction form
    401.60/603.30 = 390.80/x
  3. Step 3: Cross multiply
    401.60x = 603.30 × 390.80
  4. Step 4: Simplify right side
    401.60x = 235,769.64
  5. Step 5: Solve for x
    x = 235,769.64/401.60
  6. Step 6: Final answer
    x = 587.08

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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.