Question

Angle ADB=70° and triangle ABC is isosceles . If Angle ABC =40° , find the measure of Angle DAC​

Answer 1

you can solve this by as given

Answer 2

The measure of angle DAC is 30°

Step-by-step explanation:

Angle ADB=70° and triangle ABC is isosceles . If Angle ABC =40°

solution :

$\angle ADB + \angle ADC = 180^\circ$ (linear pair )

$70 + \angle ADC = 180^\circ\\\angle ADC = 180-70\\\angle ADC = 110^\circ$

since , ABC is an isoceles triangle

that means AB = AC

therefore ,

$\angle B = \angle C = 40^\circ$

(angle opposite to equal sides are equal )

now in triangle DAC

$\angle DAC + \angle ADC + \angle ACD= 180^\circ$

(angle sum property)

$\angle DAC + 110 +40= 180^\circ\\\angle DAC + 150= 180^\circ\\\angle DAC= 180- 150\\\angle DAC = 30^\circ$

hence ,

The measure of angle DAC is 30°

#Learn more:

Quadrilateral ABCD is cyclic quadrilateral.If measure angle ADB=70 and measure angle BAC=30,then find measure angle ABC

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