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Finding the Fourth Proportional to 498.65, 687.79 and 405.39

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Solution

The fourth proportional to 498.65, 687.79 and 405.39 is: 559.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    498.65 : 687.79 = 405.39 : x
  2. Step 2: Convert to fraction form
    498.65/687.79 = 405.39/x
  3. Step 3: Cross multiply
    498.65x = 687.79 × 405.39
  4. Step 4: Simplify right side
    498.65x = 278,823.19
  5. Step 5: Solve for x
    x = 278,823.19/498.65
  6. Step 6: Final answer
    x = 559.16

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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.