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Finding the Fourth Proportional to 969.76, 1,338.71 and 620.65

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Solution

The fourth proportional to 969.76, 1,338.71 and 620.65 is: 856.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.76 : 1,338.71 = 620.65 : x
  2. Step 2: Convert to fraction form
    969.76/1,338.71 = 620.65/x
  3. Step 3: Cross multiply
    969.76x = 1,338.71 × 620.65
  4. Step 4: Simplify right side
    969.76x = 830,870.36
  5. Step 5: Solve for x
    x = 830,870.36/969.76
  6. Step 6: Final answer
    x = 856.78

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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.