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Finding the Fourth Proportional to 1,408, 2,112.30 and 638.50

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Solution

The fourth proportional to 1,408, 2,112.30 and 638.50 is: 957.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,408 : 2,112.30 = 638.50 : x
  2. Step 2: Convert to fraction form
    1,408/2,112.30 = 638.50/x
  3. Step 3: Cross multiply
    1,408x = 2,112.30 × 638.50
  4. Step 4: Simplify right side
    1,408x = 1,348,703.55
  5. Step 5: Solve for x
    x = 1,348,703.55/1,408
  6. Step 6: Final answer
    x = 957.89

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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.