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Finding the Fourth Proportional to 699.78, 965.74 and 405.15

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Solution

The fourth proportional to 699.78, 965.74 and 405.15 is: 559.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    699.78 : 965.74 = 405.15 : x
  2. Step 2: Convert to fraction form
    699.78/965.74 = 405.15/x
  3. Step 3: Cross multiply
    699.78x = 965.74 × 405.15
  4. Step 4: Simplify right side
    699.78x = 391,272.99
  5. Step 5: Solve for x
    x = 391,272.99/699.78
  6. Step 6: Final answer
    x = 559.14

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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.