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Finding the Fourth Proportional to 860.19, 1,290.13 and 391.55

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Solution

The fourth proportional to 860.19, 1,290.13 and 391.55 is: 587.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.19 : 1,290.13 = 391.55 : x
  2. Step 2: Convert to fraction form
    860.19/1,290.13 = 391.55/x
  3. Step 3: Cross multiply
    860.19x = 1,290.13 × 391.55
  4. Step 4: Simplify right side
    860.19x = 505,145.22
  5. Step 5: Solve for x
    x = 505,145.22/860.19
  6. Step 6: Final answer
    x = 587.25

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.