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Finding the Fourth Proportional to 638.28, 880.80 and 390.01

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Solution

The fourth proportional to 638.28, 880.80 and 390.01 is: 538.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.28 : 880.80 = 390.01 : x
  2. Step 2: Convert to fraction form
    638.28/880.80 = 390.01/x
  3. Step 3: Cross multiply
    638.28x = 880.80 × 390.01
  4. Step 4: Simplify right side
    638.28x = 343,519.99
  5. Step 5: Solve for x
    x = 343,519.99/638.28
  6. Step 6: Final answer
    x = 538.20

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.