You can do that by simply measuring the main angle and then measuring each of the two angles. If you bisected the angle correctly, you will find that each of the two angles is equal to half the original.
You can measure the angle by following these steps:
1- Place the straightedge on the base of the angle.
2- Slide the protractor over it until the vertex of the angle is at the zero of the protractor.
3- Measure the angle.
It is 12 because there are 180 degrees in a set of supplementary angles and 12 times 10 equals 120, plus 60 equals 180.
Answer:
Step-by-step explanation:
According to the drawing we can see the lines
- A) LI, yes
- B) GJ, yes
- C) CJ, no
- D) BE, yes
- E) FA, no
1. Angles ADC and CDB are supplementary, thus
m∠ADC+m∠CDB=180°.
Since m∠ADC=115°, you have that m∠CDB=180°-115°=65°.
2. Triangle BCD is isosceles triangle, because it has two congruent sides CB and CD. The base of this triangle is segment BD. Angles that are adjacent to the base of isosceles triangle are congruent, then
m∠CDB=m∠CBD=65°.
The sum of the measures of interior angles of triangle is 180°, therefore,
m∠CDB+m∠CBD+m∠BCD=180° and
m∠BCD=180°-65°-65°=50°.
3. Triangle ABC is isosceles, with base BC. Then
m∠ABC=m∠ACB.
From the previous you have that m∠ABC=65° (angle ABC is exactly angle CBD). So
m∠ACB=65°.
4. Angles BCD and DCA together form angle ACB. This gives you
m∠ACB=m∠ACD+m∠BCD,
m∠ACD=65°-50°=15°.
Answer: 15°.
