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Finding the Fourth Proportional to 869.28, 1,303.20 and 638.16

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Solution

The fourth proportional to 869.28, 1,303.20 and 638.16 is: 956.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.28 : 1,303.20 = 638.16 : x
  2. Step 2: Convert to fraction form
    869.28/1,303.20 = 638.16/x
  3. Step 3: Cross multiply
    869.28x = 1,303.20 × 638.16
  4. Step 4: Simplify right side
    869.28x = 831,650.11
  5. Step 5: Solve for x
    x = 831,650.11/869.28
  6. Step 6: Final answer
    x = 956.71

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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.