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Finding the Fourth Proportional to 978.24, 1,351.72 and 783.36

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Solution

The fourth proportional to 978.24, 1,351.72 and 783.36 is: 1,082.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.24 : 1,351.72 = 783.36 : x
  2. Step 2: Convert to fraction form
    978.24/1,351.72 = 783.36/x
  3. Step 3: Cross multiply
    978.24x = 1,351.72 × 783.36
  4. Step 4: Simplify right side
    978.24x = 1,058,883.38
  5. Step 5: Solve for x
    x = 1,058,883.38/978.24
  6. Step 6: Final answer
    x = 1,082.44

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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.