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Finding the Fourth Proportional to 770.91, 1,064.21 and 491.53

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Solution

The fourth proportional to 770.91, 1,064.21 and 491.53 is: 678.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.91 : 1,064.21 = 491.53 : x
  2. Step 2: Convert to fraction form
    770.91/1,064.21 = 491.53/x
  3. Step 3: Cross multiply
    770.91x = 1,064.21 × 491.53
  4. Step 4: Simplify right side
    770.91x = 523,093.70
  5. Step 5: Solve for x
    x = 523,093.70/770.91
  6. Step 6: Final answer
    x = 678.54

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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.