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Finding the Fourth Proportional to 1,287.19, 1,776.72 and 790.56

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Solution

The fourth proportional to 1,287.19, 1,776.72 and 790.56 is: 1,091.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.19 : 1,776.72 = 790.56 : x
  2. Step 2: Convert to fraction form
    1,287.19/1,776.72 = 790.56/x
  3. Step 3: Cross multiply
    1,287.19x = 1,776.72 × 790.56
  4. Step 4: Simplify right side
    1,287.19x = 1,404,590.93
  5. Step 5: Solve for x
    x = 1,404,590.93/1,287.19
  6. Step 6: Final answer
    x = 1,091.21

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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.