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Finding the Fourth Proportional to 785.16, 1,081.05 and 666.90

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Solution

The fourth proportional to 785.16, 1,081.05 and 666.90 is: 918.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.16 : 1,081.05 = 666.90 : x
  2. Step 2: Convert to fraction form
    785.16/1,081.05 = 666.90/x
  3. Step 3: Cross multiply
    785.16x = 1,081.05 × 666.90
  4. Step 4: Simplify right side
    785.16x = 720,952.25
  5. Step 5: Solve for x
    x = 720,952.25/785.16
  6. Step 6: Final answer
    x = 918.22

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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.