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Finding the Fourth Proportional to 785.18, 1,178.18 and 438.30

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Solution

The fourth proportional to 785.18, 1,178.18 and 438.30 is: 657.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    785.18 : 1,178.18 = 438.30 : x
  2. Step 2: Convert to fraction form
    785.18/1,178.18 = 438.30/x
  3. Step 3: Cross multiply
    785.18x = 1,178.18 × 438.30
  4. Step 4: Simplify right side
    785.18x = 516,395.75
  5. Step 5: Solve for x
    x = 516,395.75/785.18
  6. Step 6: Final answer
    x = 657.68

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Double scale
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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.