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Finding the Fourth Proportional to 715.61, 987.56 and 405.11

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Solution

The fourth proportional to 715.61, 987.56 and 405.11 is: 559.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.61 : 987.56 = 405.11 : x
  2. Step 2: Convert to fraction form
    715.61/987.56 = 405.11/x
  3. Step 3: Cross multiply
    715.61x = 987.56 × 405.11
  4. Step 4: Simplify right side
    715.61x = 400,068.41
  5. Step 5: Solve for x
    x = 400,068.41/715.61
  6. Step 6: Final answer
    x = 559.06

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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.