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Finding the Fourth Proportional to 770.90, 1,063.86 and 421.60

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Solution

The fourth proportional to 770.90, 1,063.86 and 421.60 is: 581.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.90 : 1,063.86 = 421.60 : x
  2. Step 2: Convert to fraction form
    770.90/1,063.86 = 421.60/x
  3. Step 3: Cross multiply
    770.90x = 1,063.86 × 421.60
  4. Step 4: Simplify right side
    770.90x = 448,523.38
  5. Step 5: Solve for x
    x = 448,523.38/770.90
  6. Step 6: Final answer
    x = 581.82

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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.