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Finding the Fourth Proportional to 720.80, 992.40 and 672.80

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Solution

The fourth proportional to 720.80, 992.40 and 672.80 is: 926.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.80 : 992.40 = 672.80 : x
  2. Step 2: Convert to fraction form
    720.80/992.40 = 672.80/x
  3. Step 3: Cross multiply
    720.80x = 992.40 × 672.80
  4. Step 4: Simplify right side
    720.80x = 667,686.72
  5. Step 5: Solve for x
    x = 667,686.72/720.80
  6. Step 6: Final answer
    x = 926.31

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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.