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Finding the Fourth Proportional to 1,179.40, 1,629.20 and 920.80

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Solution

The fourth proportional to 1,179.40, 1,629.20 and 920.80 is: 1,271.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,179.40 : 1,629.20 = 920.80 : x
  2. Step 2: Convert to fraction form
    1,179.40/1,629.20 = 920.80/x
  3. Step 3: Cross multiply
    1,179.40x = 1,629.20 × 920.80
  4. Step 4: Simplify right side
    1,179.40x = 1,500,167.36
  5. Step 5: Solve for x
    x = 1,500,167.36/1,179.40
  6. Step 6: Final answer
    x = 1,271.98

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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.