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Finding the Fourth Proportional to 770.54, 1,155 and 380

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Solution

The fourth proportional to 770.54, 1,155 and 380 is: 569.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.54 : 1,155 = 380 : x
  2. Step 2: Convert to fraction form
    770.54/1,155 = 380/x
  3. Step 3: Cross multiply
    770.54x = 1,155 × 380
  4. Step 4: Simplify right side
    770.54x = 438,900
  5. Step 5: Solve for x
    x = 438,900/770.54
  6. Step 6: Final answer
    x = 569.60

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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.