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Finding the Fourth Proportional to 685.92, 1,020.36 and 678.96

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Solution

The fourth proportional to 685.92, 1,020.36 and 678.96 is: 1,010.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.92 : 1,020.36 = 678.96 : x
  2. Step 2: Convert to fraction form
    685.92/1,020.36 = 678.96/x
  3. Step 3: Cross multiply
    685.92x = 1,020.36 × 678.96
  4. Step 4: Simplify right side
    685.92x = 692,783.63
  5. Step 5: Solve for x
    x = 692,783.63/685.92
  6. Step 6: Final answer
    x = 1,010.01

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.