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Finding the Fourth Proportional to 770.61, 1,155.79 and 380.50

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Solution

The fourth proportional to 770.61, 1,155.79 and 380.50 is: 570.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.61 : 1,155.79 = 380.50 : x
  2. Step 2: Convert to fraction form
    770.61/1,155.79 = 380.50/x
  3. Step 3: Cross multiply
    770.61x = 1,155.79 × 380.50
  4. Step 4: Simplify right side
    770.61x = 439,778.10
  5. Step 5: Solve for x
    x = 439,778.10/770.61
  6. Step 6: Final answer
    x = 570.69

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.