Home / 840.21-1,260.90-580.80

Finding the Fourth Proportional to 840.21, 1,260.90 and 580.80

Calculator

Solution

The fourth proportional to 840.21, 1,260.90 and 580.80 is: 871.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.21 : 1,260.90 = 580.80 : x
  2. Step 2: Convert to fraction form
    840.21/1,260.90 = 580.80/x
  3. Step 3: Cross multiply
    840.21x = 1,260.90 × 580.80
  4. Step 4: Simplify right side
    840.21x = 732,330.72
  5. Step 5: Solve for x
    x = 732,330.72/840.21
  6. Step 6: Final answer
    x = 871.60

Related Problems

Find fourth proportional to 420.11, 630.45 and 290.40
Half scale
Find fourth proportional to 1,680.42, 2,521.80 and 1,161.60
Double scale
Find fourth proportional to 841.21, 1,262.40 and 581.80
Similar ratio
Find fourth proportional to 1,260.32, 1,891.35 and 871.20
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.