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Finding the Fourth Proportional to 858.85, 1,185.12 and 485.80

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Solution

The fourth proportional to 858.85, 1,185.12 and 485.80 is: 670.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.85 : 1,185.12 = 485.80 : x
  2. Step 2: Convert to fraction form
    858.85/1,185.12 = 485.80/x
  3. Step 3: Cross multiply
    858.85x = 1,185.12 × 485.80
  4. Step 4: Simplify right side
    858.85x = 575,731.30
  5. Step 5: Solve for x
    x = 575,731.30/858.85
  6. Step 6: Final answer
    x = 670.35

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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.