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Finding the Fourth Proportional to 858.87, 1,185.15 and 485.79

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Solution

The fourth proportional to 858.87, 1,185.15 and 485.79 is: 670.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.87 : 1,185.15 = 485.79 : x
  2. Step 2: Convert to fraction form
    858.87/1,185.15 = 485.79/x
  3. Step 3: Cross multiply
    858.87x = 1,185.15 × 485.79
  4. Step 4: Simplify right side
    858.87x = 575,734.02
  5. Step 5: Solve for x
    x = 575,734.02/858.87
  6. Step 6: Final answer
    x = 670.34

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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.