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Finding the Fourth Proportional to 715.95, 987.95 and 405.45

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Solution

The fourth proportional to 715.95, 987.95 and 405.45 is: 559.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.95 : 987.95 = 405.45 : x
  2. Step 2: Convert to fraction form
    715.95/987.95 = 405.45/x
  3. Step 3: Cross multiply
    715.95x = 987.95 × 405.45
  4. Step 4: Simplify right side
    715.95x = 400,562.30
  5. Step 5: Solve for x
    x = 400,562.30/715.95
  6. Step 6: Final answer
    x = 559.48

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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.