Question

find the angle measure. then classify the angle.

1. m∠bod
2. m∠aoe
3. m∠coe
4. m∠cod

describe and correct the error in finding the angle measure. use the above diagram.

1. m∠boc = 25°
2. m∠doe = 65°

Explanation:

Step1: Identify zero - degree line

For $\angle BOD$, zero - degree line is $OB$.

Step2: Read inner scale

Read inner scale where ray $OD$ intersects protractor, getting $120^{\circ}$. Since $90^{\circ}<120^{\circ}<180^{\circ}$, it's obtuse.

Step3: For $\angle AOE$

Zero - degree line is $OA$, read outer scale where $OE$ intersects, getting $140^{\circ}$, obtuse as $90^{\circ}<140^{\circ}<180^{\circ}$.

Step4: For $\angle COE$

Zero - degree line is $OC$, read outer scale where $OE$ intersects, getting $80^{\circ}$, acute as $0^{\circ}<80^{\circ}<90^{\circ}$.

Step5: For $\angle COD$

Zero - degree line is $OC$, read inner scale where $OD$ intersects, getting $40^{\circ}$, acute as $0^{\circ}<40^{\circ}<90^{\circ}$.

Step6: For $\angle BOC$

Zero - degree line is $OB$. Should read outer scale. Actual measure is $155^{\circ}$, obtuse.

Step7: For $\angle DOE$

Zero - degree line is $OD$. Should read inner scale. Actual measure is $25^{\circ}$, acute.

Answer:

1. $m\angle BOD = 120^{\circ}$, Obtuse angle
2. $m\angle AOE = 140^{\circ}$, Obtuse angle
3. $m\angle COE = 80^{\circ}$, Acute angle
4. $m\angle COD = 40^{\circ}$, Acute angle
5. Error: Read the wrong scale. Correct answer: $m\angle BOC=155^{\circ}$, Obtuse angle
6. Error: Read the wrong scale. Correct answer: $m\angle DOE = 25^{\circ}$, Acute angle