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Finding the Fourth Proportional to 427.16, 639.44 and 390.18

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Solution

The fourth proportional to 427.16, 639.44 and 390.18 is: 584.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.16 : 639.44 = 390.18 : x
  2. Step 2: Convert to fraction form
    427.16/639.44 = 390.18/x
  3. Step 3: Cross multiply
    427.16x = 639.44 × 390.18
  4. Step 4: Simplify right side
    427.16x = 249,496.70
  5. Step 5: Solve for x
    x = 249,496.70/427.16
  6. Step 6: Final answer
    x = 584.08

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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.