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Finding the Fourth Proportional to 687.74, 1,031.67 and 302.78

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Solution

The fourth proportional to 687.74, 1,031.67 and 302.78 is: 454.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.74 : 1,031.67 = 302.78 : x
  2. Step 2: Convert to fraction form
    687.74/1,031.67 = 302.78/x
  3. Step 3: Cross multiply
    687.74x = 1,031.67 × 302.78
  4. Step 4: Simplify right side
    687.74x = 312,369.04
  5. Step 5: Solve for x
    x = 312,369.04/687.74
  6. Step 6: Final answer
    x = 454.20

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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.