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Finding the Fourth Proportional to 860.15, 1,290.15 and 312.19

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Solution

The fourth proportional to 860.15, 1,290.15 and 312.19 is: 468.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.15 : 1,290.15 = 312.19 : x
  2. Step 2: Convert to fraction form
    860.15/1,290.15 = 312.19/x
  3. Step 3: Cross multiply
    860.15x = 1,290.15 × 312.19
  4. Step 4: Simplify right side
    860.15x = 402,768.70
  5. Step 5: Solve for x
    x = 402,768.70/860.15
  6. Step 6: Final answer
    x = 468.25

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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.