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Finding the Fourth Proportional to 1,307.12, 1,959.42 and 728.78

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Solution

The fourth proportional to 1,307.12, 1,959.42 and 728.78 is: 1,092.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,307.12 : 1,959.42 = 728.78 : x
  2. Step 2: Convert to fraction form
    1,307.12/1,959.42 = 728.78/x
  3. Step 3: Cross multiply
    1,307.12x = 1,959.42 × 728.78
  4. Step 4: Simplify right side
    1,307.12x = 1,427,986.11
  5. Step 5: Solve for x
    x = 1,427,986.11/1,307.12
  6. Step 6: Final answer
    x = 1,092.47

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.