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Finding the Fourth Proportional to 485.98, 670.74 and 311.32

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Solution

The fourth proportional to 485.98, 670.74 and 311.32 is: 429.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.98 : 670.74 = 311.32 : x
  2. Step 2: Convert to fraction form
    485.98/670.74 = 311.32/x
  3. Step 3: Cross multiply
    485.98x = 670.74 × 311.32
  4. Step 4: Simplify right side
    485.98x = 208,814.78
  5. Step 5: Solve for x
    x = 208,814.78/485.98
  6. Step 6: Final answer
    x = 429.68

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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.