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Finding the Fourth Proportional to 770.88, 1,156.21 and 380.78

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Solution

The fourth proportional to 770.88, 1,156.21 and 380.78 is: 571.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.88 : 1,156.21 = 380.78 : x
  2. Step 2: Convert to fraction form
    770.88/1,156.21 = 380.78/x
  3. Step 3: Cross multiply
    770.88x = 1,156.21 × 380.78
  4. Step 4: Simplify right side
    770.88x = 440,261.64
  5. Step 5: Solve for x
    x = 440,261.64/770.88
  6. Step 6: Final answer
    x = 571.12

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1.5x scale

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.