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Finding the Fourth Proportional to 882.40, 1,320.90 and 639.40

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Solution

The fourth proportional to 882.40, 1,320.90 and 639.40 is: 957.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    882.40 : 1,320.90 = 639.40 : x
  2. Step 2: Convert to fraction form
    882.40/1,320.90 = 639.40/x
  3. Step 3: Cross multiply
    882.40x = 1,320.90 × 639.40
  4. Step 4: Simplify right side
    882.40x = 844,583.46
  5. Step 5: Solve for x
    x = 844,583.46/882.40
  6. Step 6: Final answer
    x = 957.14

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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.