Home / 78-107.66-55

Finding the Fourth Proportional to 78, 107.66 and 55

Calculator

Solution

The fourth proportional to 78, 107.66 and 55 is: 75.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    78 : 107.66 = 55 : x
  2. Step 2: Convert to fraction form
    78/107.66 = 55/x
  3. Step 3: Cross multiply
    78x = 107.66 × 55
  4. Step 4: Simplify right side
    78x = 5,921.30
  5. Step 5: Solve for x
    x = 5,921.30/78
  6. Step 6: Final answer
    x = 75.91

Related Problems

Find fourth proportional to 39, 53.83 and 27.50
Half scale
Find fourth proportional to 156, 215.32 and 110
Double scale
Find fourth proportional to 79, 109.04 and 56
Similar ratio
Find fourth proportional to 117, 161.49 and 82.50
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.