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Finding the Fourth Proportional to 688.65, 1,031.21 and 380.16

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Solution

The fourth proportional to 688.65, 1,031.21 and 380.16 is: 569.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.65 : 1,031.21 = 380.16 : x
  2. Step 2: Convert to fraction form
    688.65/1,031.21 = 380.16/x
  3. Step 3: Cross multiply
    688.65x = 1,031.21 × 380.16
  4. Step 4: Simplify right side
    688.65x = 392,024.79
  5. Step 5: Solve for x
    x = 392,024.79/688.65
  6. Step 6: Final answer
    x = 569.27

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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.