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Finding the Fourth Proportional to 790.78, 1,091.34 and 685.08

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Solution

The fourth proportional to 790.78, 1,091.34 and 685.08 is: 945.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    790.78 : 1,091.34 = 685.08 : x
  2. Step 2: Convert to fraction form
    790.78/1,091.34 = 685.08/x
  3. Step 3: Cross multiply
    790.78x = 1,091.34 × 685.08
  4. Step 4: Simplify right side
    790.78x = 747,655.21
  5. Step 5: Solve for x
    x = 747,655.21/790.78
  6. Step 6: Final answer
    x = 945.47

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1.5x scale

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.