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Finding the Fourth Proportional to 1,420.79, 1,960.21 and 860.29

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Solution

The fourth proportional to 1,420.79, 1,960.21 and 860.29 is: 1,186.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.79 : 1,960.21 = 860.29 : x
  2. Step 2: Convert to fraction form
    1,420.79/1,960.21 = 860.29/x
  3. Step 3: Cross multiply
    1,420.79x = 1,960.21 × 860.29
  4. Step 4: Simplify right side
    1,420.79x = 1,686,349.06
  5. Step 5: Solve for x
    x = 1,686,349.06/1,420.79
  6. Step 6: Final answer
    x = 1,186.91

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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.