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Finding the Fourth Proportional to 687.40, 1,031.21 and 248.69

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Solution

The fourth proportional to 687.40, 1,031.21 and 248.69 is: 373.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.40 : 1,031.21 = 248.69 : x
  2. Step 2: Convert to fraction form
    687.40/1,031.21 = 248.69/x
  3. Step 3: Cross multiply
    687.40x = 1,031.21 × 248.69
  4. Step 4: Simplify right side
    687.40x = 256,448.10
  5. Step 5: Solve for x
    x = 256,448.10/687.40
  6. Step 6: Final answer
    x = 373.07

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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.