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Finding the Fourth Proportional to 642.90, 886.89 and 380.88

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Solution

The fourth proportional to 642.90, 886.89 and 380.88 is: 525.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.90 : 886.89 = 380.88 : x
  2. Step 2: Convert to fraction form
    642.90/886.89 = 380.88/x
  3. Step 3: Cross multiply
    642.90x = 886.89 × 380.88
  4. Step 4: Simplify right side
    642.90x = 337,798.66
  5. Step 5: Solve for x
    x = 337,798.66/642.90
  6. Step 6: Final answer
    x = 525.43

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1.5x scale

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.