Home / 492.21-678.65-398.61

Finding the Fourth Proportional to 492.21, 678.65 and 398.61

Calculator

Solution

The fourth proportional to 492.21, 678.65 and 398.61 is: 549.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    492.21 : 678.65 = 398.61 : x
  2. Step 2: Convert to fraction form
    492.21/678.65 = 398.61/x
  3. Step 3: Cross multiply
    492.21x = 678.65 × 398.61
  4. Step 4: Simplify right side
    492.21x = 270,514.68
  5. Step 5: Solve for x
    x = 270,514.68/492.21
  6. Step 6: Final answer
    x = 549.59

Related Problems

Find fourth proportional to 246.11, 339.32 and 199.31
Half scale
Find fourth proportional to 984.42, 1,357.29 and 797.22
Double scale
Find fourth proportional to 493.21, 680.02 and 399.61
Similar ratio
Find fourth proportional to 738.32, 1,017.97 and 597.92
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.