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Finding the Fourth Proportional to 1,420.40, 1,960.10 and 790.90

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Solution

The fourth proportional to 1,420.40, 1,960.10 and 790.90 is: 1,091.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.40 : 1,960.10 = 790.90 : x
  2. Step 2: Convert to fraction form
    1,420.40/1,960.10 = 790.90/x
  3. Step 3: Cross multiply
    1,420.40x = 1,960.10 × 790.90
  4. Step 4: Simplify right side
    1,420.40x = 1,550,237.20
  5. Step 5: Solve for x
    x = 1,550,237.20/1,420.40
  6. Step 6: Final answer
    x = 1,091.41

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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.