Question

Please help me, this is frustrating!

Answer 1

A) mes ∠ DAB) = mes ARC DAB/2

if mes ARC DAB = 40° , then mes DAB = 20

b) ∠ BDA  is inscribed in half cercle, so its mesure is 90°

c) ∠DBA =90° - 20° = 70° (COMPLEMENTARY angles in a right triangle)

d) LENGTH OF ARC DB:

The central angle DCB = mes ARC DB = 40°;

 Arc LENGTH = (40°) * (2πR)/360°, with R = 12 and π ≈ 3.14

Arc Length = (40°)*2*3.14*12/360 = 8.37 CM

Answer 2

Check the picture below


for the DB length, make sure your calculator is in Degree mode, since the angles are in degrees.