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Finding the Fourth Proportional to 1,678.64, 2,517.96 and 638.40

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Solution

The fourth proportional to 1,678.64, 2,517.96 and 638.40 is: 957.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,678.64 : 2,517.96 = 638.40 : x
  2. Step 2: Convert to fraction form
    1,678.64/2,517.96 = 638.40/x
  3. Step 3: Cross multiply
    1,678.64x = 2,517.96 × 638.40
  4. Step 4: Simplify right side
    1,678.64x = 1,607,453.07
  5. Step 5: Solve for x
    x = 1,607,453.07/1,678.64
  6. Step 6: Final answer
    x = 957.59

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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.