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Finding the Fourth Proportional to 993.21, 1,370.06 and 643.91

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Solution

The fourth proportional to 993.21, 1,370.06 and 643.91 is: 888.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    993.21 : 1,370.06 = 643.91 : x
  2. Step 2: Convert to fraction form
    993.21/1,370.06 = 643.91/x
  3. Step 3: Cross multiply
    993.21x = 1,370.06 × 643.91
  4. Step 4: Simplify right side
    993.21x = 882,185.26
  5. Step 5: Solve for x
    x = 882,185.26/993.21
  6. Step 6: Final answer
    x = 888.22

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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.