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Finding the Fourth Proportional to 689.13, 1,031.93 and 380.64

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Solution

The fourth proportional to 689.13, 1,031.93 and 380.64 is: 569.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.13 : 1,031.93 = 380.64 : x
  2. Step 2: Convert to fraction form
    689.13/1,031.93 = 380.64/x
  3. Step 3: Cross multiply
    689.13x = 1,031.93 × 380.64
  4. Step 4: Simplify right side
    689.13x = 392,793.84
  5. Step 5: Solve for x
    x = 392,793.84/689.13
  6. Step 6: Final answer
    x = 569.99

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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.