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Finding the Fourth Proportional to 486.90, 671.58 and 312.30

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Solution

The fourth proportional to 486.90, 671.58 and 312.30 is: 430.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.90 : 671.58 = 312.30 : x
  2. Step 2: Convert to fraction form
    486.90/671.58 = 312.30/x
  3. Step 3: Cross multiply
    486.90x = 671.58 × 312.30
  4. Step 4: Simplify right side
    486.90x = 209,734.43
  5. Step 5: Solve for x
    x = 209,734.43/486.90
  6. Step 6: Final answer
    x = 430.75

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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.