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Finding the Fourth Proportional to 1,420.20, 1,959.92 and 790.80

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Solution

The fourth proportional to 1,420.20, 1,959.92 and 790.80 is: 1,091.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.20 : 1,959.92 = 790.80 : x
  2. Step 2: Convert to fraction form
    1,420.20/1,959.92 = 790.80/x
  3. Step 3: Cross multiply
    1,420.20x = 1,959.92 × 790.80
  4. Step 4: Simplify right side
    1,420.20x = 1,549,904.74
  5. Step 5: Solve for x
    x = 1,549,904.74/1,420.20
  6. Step 6: Final answer
    x = 1,091.33

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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.