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Finding the Fourth Proportional to 970.87, 1,340.91 and 640.77

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Solution

The fourth proportional to 970.87, 1,340.91 and 640.77 is: 884.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.87 : 1,340.91 = 640.77 : x
  2. Step 2: Convert to fraction form
    970.87/1,340.91 = 640.77/x
  3. Step 3: Cross multiply
    970.87x = 1,340.91 × 640.77
  4. Step 4: Simplify right side
    970.87x = 859,208.20
  5. Step 5: Solve for x
    x = 859,208.20/970.87
  6. Step 6: Final answer
    x = 884.99

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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.