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Finding the Fourth Proportional to 688.58, 1,031.90 and 380.57

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Solution

The fourth proportional to 688.58, 1,031.90 and 380.57 is: 570.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.58 : 1,031.90 = 380.57 : x
  2. Step 2: Convert to fraction form
    688.58/1,031.90 = 380.57/x
  3. Step 3: Cross multiply
    688.58x = 1,031.90 × 380.57
  4. Step 4: Simplify right side
    688.58x = 392,708.28
  5. Step 5: Solve for x
    x = 392,708.28/688.58
  6. Step 6: Final answer
    x = 570.32

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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.