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Finding the Fourth Proportional to 990.64, 1,487.18 and 579.97

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Solution

The fourth proportional to 990.64, 1,487.18 and 579.97 is: 870.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.64 : 1,487.18 = 579.97 : x
  2. Step 2: Convert to fraction form
    990.64/1,487.18 = 579.97/x
  3. Step 3: Cross multiply
    990.64x = 1,487.18 × 579.97
  4. Step 4: Simplify right side
    990.64x = 862,519.78
  5. Step 5: Solve for x
    x = 862,519.78/990.64
  6. Step 6: Final answer
    x = 870.67

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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.