Question

The sketch shows a triangle and its

exterior angles. Find the measure of
angle IAC.
Show all your calculations. Justify your
answer.
MDHA = 128"
MZHCA = 46°

Answer 1

<IAC=°98

Explanation:

<DHA + CHA = 180 SUPPLEMENTARY ANGLE

128 +CHA=180

<CHA=52

<CHA + <HAC+<ACH=180 b/c it is triangle

46 +52+HAC= 180

<HAC= 180-98

<HAC= 82

<HAC + <IAC= 180. Supplementary angle

82+<IAC=180

<IAC=180-82

<IAC=98

Answer 2

∠ IAC = 98°

Explanation:

The sum of the exterior angle = 360°

∠ HCB = 180° - 46° = 134° ( adjacent angles )

Thus

∠ IAC + 128° + 134° = 360°, that is

∠ IAC + 262° = 360° ( subtract 262° from both sides )

∠ IAC = 98°