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Finding the Fourth Proportional to 1,139.15, 1,570.15 and 765.95

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Solution

The fourth proportional to 1,139.15, 1,570.15 and 765.95 is: 1,055.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.15 : 1,570.15 = 765.95 : x
  2. Step 2: Convert to fraction form
    1,139.15/1,570.15 = 765.95/x
  3. Step 3: Cross multiply
    1,139.15x = 1,570.15 × 765.95
  4. Step 4: Simplify right side
    1,139.15x = 1,202,644.71
  5. Step 5: Solve for x
    x = 1,202,644.71/1,139.15
  6. Step 6: Final answer
    x = 1,055.74

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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.