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Finding the Fourth Proportional to 975.40, 1,461.78 and 428.05

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Solution

The fourth proportional to 975.40, 1,461.78 and 428.05 is: 641.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    975.40 : 1,461.78 = 428.05 : x
  2. Step 2: Convert to fraction form
    975.40/1,461.78 = 428.05/x
  3. Step 3: Cross multiply
    975.40x = 1,461.78 × 428.05
  4. Step 4: Simplify right side
    975.40x = 625,714.93
  5. Step 5: Solve for x
    x = 625,714.93/975.40
  6. Step 6: Final answer
    x = 641.50

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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.