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Finding the Fourth Proportional to 990.83, 1,488.53 and 621.78

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Solution

The fourth proportional to 990.83, 1,488.53 and 621.78 is: 934.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.83 : 1,488.53 = 621.78 : x
  2. Step 2: Convert to fraction form
    990.83/1,488.53 = 621.78/x
  3. Step 3: Cross multiply
    990.83x = 1,488.53 × 621.78
  4. Step 4: Simplify right side
    990.83x = 925,539.74
  5. Step 5: Solve for x
    x = 925,539.74/990.83
  6. Step 6: Final answer
    x = 934.11

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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.