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Finding the Fourth Proportional to 427.28, 637.28 and 390.84

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Solution

The fourth proportional to 427.28, 637.28 and 390.84 is: 582.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.28 : 637.28 = 390.84 : x
  2. Step 2: Convert to fraction form
    427.28/637.28 = 390.84/x
  3. Step 3: Cross multiply
    427.28x = 637.28 × 390.84
  4. Step 4: Simplify right side
    427.28x = 249,074.52
  5. Step 5: Solve for x
    x = 249,074.52/427.28
  6. Step 6: Final answer
    x = 582.93

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.