Answer:
3
Step-by-step explanation:
Answer:
Using the Angle Addition Postulate, 20 + m∠DBC = 80. So, m∠DBC = 60° using the subtraction property of equality.
Step-by-step explanation:
If point D is the interior of angle ABC, then the angle addition postulate theory states that the sum of angle ABD and angle DBC is equals to angle ABC. The angle addition postulate is used to measure the resulting angle from two angles placed side by side.
From the attached image, ∠ABD and ∠DBC are placed side by side to form ∠ABC. Given that m∠ABD = 20° and m∠ABC = 80°
Hence, using angle addition postulate:
m∠ABD + m∠DBC = m∠ABC
20 + m∠DBC = 80
subtracting 20 from both sides (subtraction property of equality)
m∠DBC = 80 - 20
m∠DBC = 60°
Step-by-step explanation:
hope you can send the questions again because your question is to long to answer everything. I answered 1,2,3,4
To determine the missing angle you simply subtract the angle you know from 180 because a flat line is 180 degrees. If it is a circle you subtract the number from 360. Hope this helps!
D = 2r => 12.6 = 2*r => r=6.3
A = π*r^2 = (3.14) * (6.3)^2 = (3.14)*(39.69) = 124.6266 which is approximately 124.63
Hope this helps!