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Finding the Fourth Proportional to 820.38, 1,135.08 and 715.69

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Solution

The fourth proportional to 820.38, 1,135.08 and 715.69 is: 990.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.38 : 1,135.08 = 715.69 : x
  2. Step 2: Convert to fraction form
    820.38/1,135.08 = 715.69/x
  3. Step 3: Cross multiply
    820.38x = 1,135.08 × 715.69
  4. Step 4: Simplify right side
    820.38x = 812,365.41
  5. Step 5: Solve for x
    x = 812,365.41/820.38
  6. Step 6: Final answer
    x = 990.23

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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.