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Finding the Fourth Proportional to 860.25, 1,290.31 and 312.56

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Solution

The fourth proportional to 860.25, 1,290.31 and 312.56 is: 468.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.25 : 1,290.31 = 312.56 : x
  2. Step 2: Convert to fraction form
    860.25/1,290.31 = 312.56/x
  3. Step 3: Cross multiply
    860.25x = 1,290.31 × 312.56
  4. Step 4: Simplify right side
    860.25x = 403,296.07
  5. Step 5: Solve for x
    x = 403,296.07/860.25
  6. Step 6: Final answer
    x = 468.81

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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.