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Finding the Fourth Proportional to 815.65, 1,125.65 and 778.75

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Solution

The fourth proportional to 815.65, 1,125.65 and 778.75 is: 1,074.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.65 : 1,125.65 = 778.75 : x
  2. Step 2: Convert to fraction form
    815.65/1,125.65 = 778.75/x
  3. Step 3: Cross multiply
    815.65x = 1,125.65 × 778.75
  4. Step 4: Simplify right side
    815.65x = 876,599.94
  5. Step 5: Solve for x
    x = 876,599.94/815.65
  6. Step 6: Final answer
    x = 1,074.73

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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.