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Finding the Fourth Proportional to 970.74, 1,340.72 and 640.63

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Solution

The fourth proportional to 970.74, 1,340.72 and 640.63 is: 884.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.74 : 1,340.72 = 640.63 : x
  2. Step 2: Convert to fraction form
    970.74/1,340.72 = 640.63/x
  3. Step 3: Cross multiply
    970.74x = 1,340.72 × 640.63
  4. Step 4: Simplify right side
    970.74x = 858,905.45
  5. Step 5: Solve for x
    x = 858,905.45/970.74
  6. Step 6: Final answer
    x = 884.79

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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.