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Finding the Fourth Proportional to 486.40, 671.34 and 311.80

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Solution

The fourth proportional to 486.40, 671.34 and 311.80 is: 430.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.40 : 671.34 = 311.80 : x
  2. Step 2: Convert to fraction form
    486.40/671.34 = 311.80/x
  3. Step 3: Cross multiply
    486.40x = 671.34 × 311.80
  4. Step 4: Simplify right side
    486.40x = 209,323.81
  5. Step 5: Solve for x
    x = 209,323.81/486.40
  6. Step 6: Final answer
    x = 430.35

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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.