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Finding the Fourth Proportional to 970.48, 1,338.78 and 638.48

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Solution

The fourth proportional to 970.48, 1,338.78 and 638.48 is: 880.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.48 : 1,338.78 = 638.48 : x
  2. Step 2: Convert to fraction form
    970.48/1,338.78 = 638.48/x
  3. Step 3: Cross multiply
    970.48x = 1,338.78 × 638.48
  4. Step 4: Simplify right side
    970.48x = 854,786.40
  5. Step 5: Solve for x
    x = 854,786.40/970.48
  6. Step 6: Final answer
    x = 880.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.