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Finding the Fourth Proportional to 858.40, 1,186.32 and 638.08

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Solution

The fourth proportional to 858.40, 1,186.32 and 638.08 is: 881.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.40 : 1,186.32 = 638.08 : x
  2. Step 2: Convert to fraction form
    858.40/1,186.32 = 638.08/x
  3. Step 3: Cross multiply
    858.40x = 1,186.32 × 638.08
  4. Step 4: Simplify right side
    858.40x = 756,967.07
  5. Step 5: Solve for x
    x = 756,967.07/858.40
  6. Step 6: Final answer
    x = 881.83

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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.