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Finding the Fourth Proportional to 990.42, 1,488.51 and 477.78

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Solution

The fourth proportional to 990.42, 1,488.51 and 477.78 is: 718.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.42 : 1,488.51 = 477.78 : x
  2. Step 2: Convert to fraction form
    990.42/1,488.51 = 477.78/x
  3. Step 3: Cross multiply
    990.42x = 1,488.51 × 477.78
  4. Step 4: Simplify right side
    990.42x = 711,180.31
  5. Step 5: Solve for x
    x = 711,180.31/990.42
  6. Step 6: Final answer
    x = 718.06

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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.