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Finding the Fourth Proportional to 486.80, 671.48 and 312.40

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Solution

The fourth proportional to 486.80, 671.48 and 312.40 is: 430.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.80 : 671.48 = 312.40 : x
  2. Step 2: Convert to fraction form
    486.80/671.48 = 312.40/x
  3. Step 3: Cross multiply
    486.80x = 671.48 × 312.40
  4. Step 4: Simplify right side
    486.80x = 209,770.35
  5. Step 5: Solve for x
    x = 209,770.35/486.80
  6. Step 6: Final answer
    x = 430.92

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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.