Home / 85-127.32-78

Finding the Fourth Proportional to 85, 127.32 and 78

Calculator

Solution

The fourth proportional to 85, 127.32 and 78 is: 116.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    85 : 127.32 = 78 : x
  2. Step 2: Convert to fraction form
    85/127.32 = 78/x
  3. Step 3: Cross multiply
    85x = 127.32 × 78
  4. Step 4: Simplify right side
    85x = 9,930.96
  5. Step 5: Solve for x
    x = 9,930.96/85
  6. Step 6: Final answer
    x = 116.83

Related Problems

Find fourth proportional to 42.50, 63.66 and 39
Half scale
Find fourth proportional to 170, 254.64 and 156
Double scale
Find fourth proportional to 86, 128.82 and 79
Similar ratio
Find fourth proportional to 127.50, 190.98 and 117
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.