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Finding the Fourth Proportional to 485.80, 670.38 and 289.36

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Solution

The fourth proportional to 485.80, 670.38 and 289.36 is: 399.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.80 : 670.38 = 289.36 : x
  2. Step 2: Convert to fraction form
    485.80/670.38 = 289.36/x
  3. Step 3: Cross multiply
    485.80x = 670.38 × 289.36
  4. Step 4: Simplify right side
    485.80x = 193,981.16
  5. Step 5: Solve for x
    x = 193,981.16/485.80
  6. Step 6: Final answer
    x = 399.30

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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.