Answer: Base angles theorem
Step-by-step explanation:
Answer:
5
Step-by-step explanation:
24 divided by 3 is 8
so 15 divided by 3 is 5
First, it's worth noting that angles on a straight line sum to 180°. We can use this information to find out the value of y:
180-52-59=69
y=69°
Another rule is that the angles in a triangle sum to 180° as well. This means that we can now find out x:
63+y+x=180
63+69+x=180
180-63-69=x
x=48°
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°.
