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Finding the Fourth Proportional to 1,247.00, 1,720.70 and 715.85

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Solution

The fourth proportional to 1,247.00, 1,720.70 and 715.85 is: 987.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.00 : 1,720.70 = 715.85 : x
  2. Step 2: Convert to fraction form
    1,247.00/1,720.70 = 715.85/x
  3. Step 3: Cross multiply
    1,247.00x = 1,720.70 × 715.85
  4. Step 4: Simplify right side
    1,247.00x = 1,231,763.10
  5. Step 5: Solve for x
    x = 1,231,763.10/1,247.00
  6. Step 6: Final answer
    x = 987.79

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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.