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Finding the Fourth Proportional to 485.90, 670.74 and 289.42

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Solution

The fourth proportional to 485.90, 670.74 and 289.42 is: 399.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.90 : 670.74 = 289.42 : x
  2. Step 2: Convert to fraction form
    485.90/670.74 = 289.42/x
  3. Step 3: Cross multiply
    485.90x = 670.74 × 289.42
  4. Step 4: Simplify right side
    485.90x = 194,125.57
  5. Step 5: Solve for x
    x = 194,125.57/485.90
  6. Step 6: Final answer
    x = 399.52

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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.