Home / 418.70-628.05-386.30

Finding the Fourth Proportional to 418.70, 628.05 and 386.30

Calculator

Solution

The fourth proportional to 418.70, 628.05 and 386.30 is: 579.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    418.70 : 628.05 = 386.30 : x
  2. Step 2: Convert to fraction form
    418.70/628.05 = 386.30/x
  3. Step 3: Cross multiply
    418.70x = 628.05 × 386.30
  4. Step 4: Simplify right side
    418.70x = 242,615.72
  5. Step 5: Solve for x
    x = 242,615.72/418.70
  6. Step 6: Final answer
    x = 579.45

Related Problems

Find fourth proportional to 209.35, 314.03 and 193.15
Half scale
Find fourth proportional to 837.40, 1,256.10 and 772.60
Double scale
Find fourth proportional to 419.70, 629.55 and 387.30
Similar ratio
Find fourth proportional to 628.05, 942.08 and 579.45
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.