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Finding the Fourth Proportional to 1,239.30, 1,709.91 and 715.32

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Solution

The fourth proportional to 1,239.30, 1,709.91 and 715.32 is: 986.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.30 : 1,709.91 = 715.32 : x
  2. Step 2: Convert to fraction form
    1,239.30/1,709.91 = 715.32/x
  3. Step 3: Cross multiply
    1,239.30x = 1,709.91 × 715.32
  4. Step 4: Simplify right side
    1,239.30x = 1,223,132.82
  5. Step 5: Solve for x
    x = 1,223,132.82/1,239.30
  6. Step 6: Final answer
    x = 986.95

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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.