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Finding the Fourth Proportional to 979.80, 1,351.80 and 630.68

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Solution

The fourth proportional to 979.80, 1,351.80 and 630.68 is: 870.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.80 : 1,351.80 = 630.68 : x
  2. Step 2: Convert to fraction form
    979.80/1,351.80 = 630.68/x
  3. Step 3: Cross multiply
    979.80x = 1,351.80 × 630.68
  4. Step 4: Simplify right side
    979.80x = 852,553.22
  5. Step 5: Solve for x
    x = 852,553.22/979.80
  6. Step 6: Final answer
    x = 870.13

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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.