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Finding the Fourth Proportional to 992.99, 1,371.32 and 643.88

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Solution

The fourth proportional to 992.99, 1,371.32 and 643.88 is: 889.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.99 : 1,371.32 = 643.88 : x
  2. Step 2: Convert to fraction form
    992.99/1,371.32 = 643.88/x
  3. Step 3: Cross multiply
    992.99x = 1,371.32 × 643.88
  4. Step 4: Simplify right side
    992.99x = 882,955.45
  5. Step 5: Solve for x
    x = 882,955.45/992.99
  6. Step 6: Final answer
    x = 889.19

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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.