Home / 216.87-324.96-139.78

Finding the Fourth Proportional to 216.87, 324.96 and 139.78

Calculator

Solution

The fourth proportional to 216.87, 324.96 and 139.78 is: 209.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.87 : 324.96 = 139.78 : x
  2. Step 2: Convert to fraction form
    216.87/324.96 = 139.78/x
  3. Step 3: Cross multiply
    216.87x = 324.96 × 139.78
  4. Step 4: Simplify right side
    216.87x = 45,422.91
  5. Step 5: Solve for x
    x = 45,422.91/216.87
  6. Step 6: Final answer
    x = 209.45

Related Problems

Find fourth proportional to 108.44, 162.48 and 69.89
Half scale
Find fourth proportional to 433.74, 649.92 and 279.56
Double scale
Find fourth proportional to 217.87, 326.46 and 140.78
Similar ratio
Find fourth proportional to 325.31, 487.44 and 209.67
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.