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Finding the Fourth Proportional to 715.42, 986.61 and 687.34

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Solution

The fourth proportional to 715.42, 986.61 and 687.34 is: 947.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.42 : 986.61 = 687.34 : x
  2. Step 2: Convert to fraction form
    715.42/986.61 = 687.34/x
  3. Step 3: Cross multiply
    715.42x = 986.61 × 687.34
  4. Step 4: Simplify right side
    715.42x = 678,136.52
  5. Step 5: Solve for x
    x = 678,136.52/715.42
  6. Step 6: Final answer
    x = 947.89

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Half scale
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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.