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Finding the Fourth Proportional to 860.28, 1,290.40 and 312.25

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Solution

The fourth proportional to 860.28, 1,290.40 and 312.25 is: 468.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.28 : 1,290.40 = 312.25 : x
  2. Step 2: Convert to fraction form
    860.28/1,290.40 = 312.25/x
  3. Step 3: Cross multiply
    860.28x = 1,290.40 × 312.25
  4. Step 4: Simplify right side
    860.28x = 402,927.40
  5. Step 5: Solve for x
    x = 402,927.40/860.28
  6. Step 6: Final answer
    x = 468.37

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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.