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Finding the Fourth Proportional to 918.75, 1,268.90 and 623.50

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Solution

The fourth proportional to 918.75, 1,268.90 and 623.50 is: 861.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.75 : 1,268.90 = 623.50 : x
  2. Step 2: Convert to fraction form
    918.75/1,268.90 = 623.50/x
  3. Step 3: Cross multiply
    918.75x = 1,268.90 × 623.50
  4. Step 4: Simplify right side
    918.75x = 791,159.15
  5. Step 5: Solve for x
    x = 791,159.15/918.75
  6. Step 6: Final answer
    x = 861.13

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Find fourth proportional to 459.38, 634.45 and 311.75
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.