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Finding the Fourth Proportional to 1,139.99, 1,573.29 and 642.65

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Solution

The fourth proportional to 1,139.99, 1,573.29 and 642.65 is: 886.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.99 : 1,573.29 = 642.65 : x
  2. Step 2: Convert to fraction form
    1,139.99/1,573.29 = 642.65/x
  3. Step 3: Cross multiply
    1,139.99x = 1,573.29 × 642.65
  4. Step 4: Simplify right side
    1,139.99x = 1,011,066.95
  5. Step 5: Solve for x
    x = 1,011,066.95/1,139.99
  6. Step 6: Final answer
    x = 886.91

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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.