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Finding the Fourth Proportional to 685.84, 1,030.56 and 642.10

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Solution

The fourth proportional to 685.84, 1,030.56 and 642.10 is: 964.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.84 : 1,030.56 = 642.10 : x
  2. Step 2: Convert to fraction form
    685.84/1,030.56 = 642.10/x
  3. Step 3: Cross multiply
    685.84x = 1,030.56 × 642.10
  4. Step 4: Simplify right side
    685.84x = 661,722.58
  5. Step 5: Solve for x
    x = 661,722.58/685.84
  6. Step 6: Final answer
    x = 964.84

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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.