Home / 493.80-740.70-420.20

Finding the Fourth Proportional to 493.80, 740.70 and 420.20

Calculator

Solution

The fourth proportional to 493.80, 740.70 and 420.20 is: 630.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    493.80 : 740.70 = 420.20 : x
  2. Step 2: Convert to fraction form
    493.80/740.70 = 420.20/x
  3. Step 3: Cross multiply
    493.80x = 740.70 × 420.20
  4. Step 4: Simplify right side
    493.80x = 311,242.14
  5. Step 5: Solve for x
    x = 311,242.14/493.80
  6. Step 6: Final answer
    x = 630.30

Related Problems

Find fourth proportional to 246.90, 370.35 and 210.10
Half scale
Find fourth proportional to 987.60, 1,481.40 and 840.40
Double scale
Find fourth proportional to 494.80, 742.20 and 421.20
Similar ratio
Find fourth proportional to 740.70, 1,111.05 and 630.30
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.