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Finding the Fourth Proportional to 990.36, 1,485.12 and 442.56

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Solution

The fourth proportional to 990.36, 1,485.12 and 442.56 is: 663.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.36 : 1,485.12 = 442.56 : x
  2. Step 2: Convert to fraction form
    990.36/1,485.12 = 442.56/x
  3. Step 3: Cross multiply
    990.36x = 1,485.12 × 442.56
  4. Step 4: Simplify right side
    990.36x = 657,254.71
  5. Step 5: Solve for x
    x = 657,254.71/990.36
  6. Step 6: Final answer
    x = 663.65

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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.