Home / 419.70-628.35-257.70

Finding the Fourth Proportional to 419.70, 628.35 and 257.70

Calculator

Solution

The fourth proportional to 419.70, 628.35 and 257.70 is: 385.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.70 : 628.35 = 257.70 : x
  2. Step 2: Convert to fraction form
    419.70/628.35 = 257.70/x
  3. Step 3: Cross multiply
    419.70x = 628.35 × 257.70
  4. Step 4: Simplify right side
    419.70x = 161,925.80
  5. Step 5: Solve for x
    x = 161,925.80/419.70
  6. Step 6: Final answer
    x = 385.81

Related Problems

Find fourth proportional to 209.85, 314.18 and 128.85
Half scale
Find fourth proportional to 839.40, 1,256.70 and 515.40
Double scale
Find fourth proportional to 420.70, 629.85 and 258.70
Similar ratio
Find fourth proportional to 629.55, 942.53 and 386.55
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.