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Finding the Fourth Proportional to 719.43, 990.45 and 639.24

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Solution

The fourth proportional to 719.43, 990.45 and 639.24 is: 880.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.43 : 990.45 = 639.24 : x
  2. Step 2: Convert to fraction form
    719.43/990.45 = 639.24/x
  3. Step 3: Cross multiply
    719.43x = 990.45 × 639.24
  4. Step 4: Simplify right side
    719.43x = 633,135.26
  5. Step 5: Solve for x
    x = 633,135.26/719.43
  6. Step 6: Final answer
    x = 880.05

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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.