Home / 74.87-103.40-57.20

Finding the Fourth Proportional to 74.87, 103.40 and 57.20

Calculator

Solution

The fourth proportional to 74.87, 103.40 and 57.20 is: 78.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    74.87 : 103.40 = 57.20 : x
  2. Step 2: Convert to fraction form
    74.87/103.40 = 57.20/x
  3. Step 3: Cross multiply
    74.87x = 103.40 × 57.20
  4. Step 4: Simplify right side
    74.87x = 5,913.89
  5. Step 5: Solve for x
    x = 5,913.89/74.87
  6. Step 6: Final answer
    x = 78.99

Related Problems

Find fourth proportional to 37.43, 51.70 and 28.60
Half scale
Find fourth proportional to 149.74, 206.80 and 114.39
Double scale
Find fourth proportional to 75.87, 104.78 and 58.20
Similar ratio
Find fourth proportional to 112.30, 155.10 and 85.79
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.