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Finding the Fourth Proportional to 1,420.70, 1,960.60 and 861.06

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Solution

The fourth proportional to 1,420.70, 1,960.60 and 861.06 is: 1,188.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.70 : 1,960.60 = 861.06 : x
  2. Step 2: Convert to fraction form
    1,420.70/1,960.60 = 861.06/x
  3. Step 3: Cross multiply
    1,420.70x = 1,960.60 × 861.06
  4. Step 4: Simplify right side
    1,420.70x = 1,688,194.24
  5. Step 5: Solve for x
    x = 1,688,194.24/1,420.70
  6. Step 6: Final answer
    x = 1,188.28

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1.5x scale

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.