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Finding the Fourth Proportional to 970.10, 1,339.62 and 621.40

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Solution

The fourth proportional to 970.10, 1,339.62 and 621.40 is: 858.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.10 : 1,339.62 = 621.40 : x
  2. Step 2: Convert to fraction form
    970.10/1,339.62 = 621.40/x
  3. Step 3: Cross multiply
    970.10x = 1,339.62 × 621.40
  4. Step 4: Simplify right side
    970.10x = 832,439.87
  5. Step 5: Solve for x
    x = 832,439.87/970.10
  6. Step 6: Final answer
    x = 858.10

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Double scale
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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.