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Finding the Fourth Proportional to 622.90, 859.95 and 390.34

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Solution

The fourth proportional to 622.90, 859.95 and 390.34 is: 538.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    622.90 : 859.95 = 390.34 : x
  2. Step 2: Convert to fraction form
    622.90/859.95 = 390.34/x
  3. Step 3: Cross multiply
    622.90x = 859.95 × 390.34
  4. Step 4: Simplify right side
    622.90x = 335,672.88
  5. Step 5: Solve for x
    x = 335,672.88/622.90
  6. Step 6: Final answer
    x = 538.89

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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.