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Finding the Fourth Proportional to 780.90, 1,077.74 and 715.29

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Solution

The fourth proportional to 780.90, 1,077.74 and 715.29 is: 987.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.90 : 1,077.74 = 715.29 : x
  2. Step 2: Convert to fraction form
    780.90/1,077.74 = 715.29/x
  3. Step 3: Cross multiply
    780.90x = 1,077.74 × 715.29
  4. Step 4: Simplify right side
    780.90x = 770,896.64
  5. Step 5: Solve for x
    x = 770,896.64/780.90
  6. Step 6: Final answer
    x = 987.19

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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.