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Finding the Fourth Proportional to 990.72, 1,484.43 and 643.62

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Solution

The fourth proportional to 990.72, 1,484.43 and 643.62 is: 964.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.72 : 1,484.43 = 643.62 : x
  2. Step 2: Convert to fraction form
    990.72/1,484.43 = 643.62/x
  3. Step 3: Cross multiply
    990.72x = 1,484.43 × 643.62
  4. Step 4: Simplify right side
    990.72x = 955,408.84
  5. Step 5: Solve for x
    x = 955,408.84/990.72
  6. Step 6: Final answer
    x = 964.36

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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.