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Finding the Fourth Proportional to 774.90, 1,069.35 and 420.82

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Solution

The fourth proportional to 774.90, 1,069.35 and 420.82 is: 580.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    774.90 : 1,069.35 = 420.82 : x
  2. Step 2: Convert to fraction form
    774.90/1,069.35 = 420.82/x
  3. Step 3: Cross multiply
    774.90x = 1,069.35 × 420.82
  4. Step 4: Simplify right side
    774.90x = 450,001.66
  5. Step 5: Solve for x
    x = 450,001.66/774.90
  6. Step 6: Final answer
    x = 580.72

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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.