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Finding the Fourth Proportional to 990.57, 1,485.63 and 638.11

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Solution

The fourth proportional to 990.57, 1,485.63 and 638.11 is: 957.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.57 : 1,485.63 = 638.11 : x
  2. Step 2: Convert to fraction form
    990.57/1,485.63 = 638.11/x
  3. Step 3: Cross multiply
    990.57x = 1,485.63 × 638.11
  4. Step 4: Simplify right side
    990.57x = 947,995.36
  5. Step 5: Solve for x
    x = 947,995.36/990.57
  6. Step 6: Final answer
    x = 957.02

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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.