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Finding the Fourth Proportional to 685.04, 1,027.80 and 428.24

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Solution

The fourth proportional to 685.04, 1,027.80 and 428.24 is: 642.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.04 : 1,027.80 = 428.24 : x
  2. Step 2: Convert to fraction form
    685.04/1,027.80 = 428.24/x
  3. Step 3: Cross multiply
    685.04x = 1,027.80 × 428.24
  4. Step 4: Simplify right side
    685.04x = 440,145.07
  5. Step 5: Solve for x
    x = 440,145.07/685.04
  6. Step 6: Final answer
    x = 642.51

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.