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Finding the Fourth Proportional to 1,108.80, 1,666.80 and 786.40

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Solution

The fourth proportional to 1,108.80, 1,666.80 and 786.40 is: 1,182.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,108.80 : 1,666.80 = 786.40 : x
  2. Step 2: Convert to fraction form
    1,108.80/1,666.80 = 786.40/x
  3. Step 3: Cross multiply
    1,108.80x = 1,666.80 × 786.40
  4. Step 4: Simplify right side
    1,108.80x = 1,310,771.52
  5. Step 5: Solve for x
    x = 1,310,771.52/1,108.80
  6. Step 6: Final answer
    x = 1,182.15

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.