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Finding the Fourth Proportional to 990.15, 1,484.51 and 643.83

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Solution

The fourth proportional to 990.15, 1,484.51 and 643.83 is: 965.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.15 : 1,484.51 = 643.83 : x
  2. Step 2: Convert to fraction form
    990.15/1,484.51 = 643.83/x
  3. Step 3: Cross multiply
    990.15x = 1,484.51 × 643.83
  4. Step 4: Simplify right side
    990.15x = 955,774.17
  5. Step 5: Solve for x
    x = 955,774.17/990.15
  6. Step 6: Final answer
    x = 965.28

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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.