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Finding the Fourth Proportional to 487, 672.06 and 280

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Solution

The fourth proportional to 487, 672.06 and 280 is: 386.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    487 : 672.06 = 280 : x
  2. Step 2: Convert to fraction form
    487/672.06 = 280/x
  3. Step 3: Cross multiply
    487x = 672.06 × 280
  4. Step 4: Simplify right side
    487x = 188,176.80
  5. Step 5: Solve for x
    x = 188,176.80/487
  6. Step 6: Final answer
    x = 386.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.