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Finding the Fourth Proportional to 485.75, 670 and 311.01

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Solution

The fourth proportional to 485.75, 670 and 311.01 is: 428.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.75 : 670 = 311.01 : x
  2. Step 2: Convert to fraction form
    485.75/670 = 311.01/x
  3. Step 3: Cross multiply
    485.75x = 670 × 311.01
  4. Step 4: Simplify right side
    485.75x = 208,376.70
  5. Step 5: Solve for x
    x = 208,376.70/485.75
  6. Step 6: Final answer
    x = 428.98

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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.