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Finding the Fourth Proportional to 419.94, 579.12 and 390.84

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Solution

The fourth proportional to 419.94, 579.12 and 390.84 is: 538.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.94 : 579.12 = 390.84 : x
  2. Step 2: Convert to fraction form
    419.94/579.12 = 390.84/x
  3. Step 3: Cross multiply
    419.94x = 579.12 × 390.84
  4. Step 4: Simplify right side
    419.94x = 226,343.26
  5. Step 5: Solve for x
    x = 226,343.26/419.94
  6. Step 6: Final answer
    x = 538.99

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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.