Home / 499.78-689.67-278.70

Finding the Fourth Proportional to 499.78, 689.67 and 278.70

Calculator

Solution

The fourth proportional to 499.78, 689.67 and 278.70 is: 384.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.78 : 689.67 = 278.70 : x
  2. Step 2: Convert to fraction form
    499.78/689.67 = 278.70/x
  3. Step 3: Cross multiply
    499.78x = 689.67 × 278.70
  4. Step 4: Simplify right side
    499.78x = 192,211.03
  5. Step 5: Solve for x
    x = 192,211.03/499.78
  6. Step 6: Final answer
    x = 384.59

Related Problems

Find fourth proportional to 249.89, 344.84 and 139.35
Half scale
Find fourth proportional to 999.56, 1,379.34 and 557.40
Double scale
Find fourth proportional to 500.78, 691.05 and 279.70
Similar ratio
Find fourth proportional to 749.67, 1,034.51 and 418.05
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.