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Finding the Fourth Proportional to 645.89, 891.31 and 351.15

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Solution

The fourth proportional to 645.89, 891.31 and 351.15 is: 484.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.89 : 891.31 = 351.15 : x
  2. Step 2: Convert to fraction form
    645.89/891.31 = 351.15/x
  3. Step 3: Cross multiply
    645.89x = 891.31 × 351.15
  4. Step 4: Simplify right side
    645.89x = 312,982.63
  5. Step 5: Solve for x
    x = 312,982.63/645.89
  6. Step 6: Final answer
    x = 484.58

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1.5x scale

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.