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Finding the Fourth Proportional to 853.38, 1,176.21 and 643.50

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Solution

The fourth proportional to 853.38, 1,176.21 and 643.50 is: 886.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.38 : 1,176.21 = 643.50 : x
  2. Step 2: Convert to fraction form
    853.38/1,176.21 = 643.50/x
  3. Step 3: Cross multiply
    853.38x = 1,176.21 × 643.50
  4. Step 4: Simplify right side
    853.38x = 756,891.14
  5. Step 5: Solve for x
    x = 756,891.14/853.38
  6. Step 6: Final answer
    x = 886.93

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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.