Examples with solutions for Ratio: Using angles in a triangle

Exercise #1

One angle in a triangle is 90°.
The ratio between the other two angles is 2:1.

What are the sizes of the other angles in the triangle?

Step-by-Step Solution

To solve this problem, let's follow these steps:

  • Step 1: Identify the given information; one angle is 90∘90^\circ, and the other two angles are in a 2:1 ratio.
  • Step 2: Set up an equation using the relationship between the angles: 90∘+2x+x=180∘90^\circ + 2x + x = 180^\circ.
  • Step 3: Solve the equation for xx.
  • Step 4: Calculate the measures of the two angles.

Now, let's work through each step.
Step 1: Given a right triangle, one angle is 90∘90^\circ, and the other two angles are in the ratio 2:1.

Step 2: Express the other two angles in terms of xx:
- One angle is 2x2x.
- The second angle is xx.

Step 3: Use the sum of angles in a triangle to write an equation:
90∘+2x+x=180∘90^\circ + 2x + x = 180^\circ.

Step 4: Simplify and solve the equation:
Combine like terms:
90∘+3x=180∘90^\circ + 3x = 180^\circ.

Subtract 90∘90^\circ from both sides:
3x=90∘3x = 90^\circ.

Divide both sides by 3:
x=30∘x = 30^\circ.

Now we can find the measures of the other angles:
The angle expressed as xx is 30∘30^\circ.
The angle expressed as 2x2x is 2×30∘=60∘2 \times 30^\circ = 60^\circ.

Therefore, the solution is that the other two angles are 60∘60^\circ and 30∘30^\circ.

Answer

60°, 30°