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Finding the Fourth Proportional to 1,238.79, 1,709.87 and 715.17

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Solution

The fourth proportional to 1,238.79, 1,709.87 and 715.17 is: 987.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.79 : 1,709.87 = 715.17 : x
  2. Step 2: Convert to fraction form
    1,238.79/1,709.87 = 715.17/x
  3. Step 3: Cross multiply
    1,238.79x = 1,709.87 × 715.17
  4. Step 4: Simplify right side
    1,238.79x = 1,222,844.15
  5. Step 5: Solve for x
    x = 1,222,844.15/1,238.79
  6. Step 6: Final answer
    x = 987.13

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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.