Answer:
The correct statements are:
I, II , III
Step-by-step explanation:
- In the given triangle i.e. ΔABC we have:
length of side AB= length of side AC= 20 units
Hence, we have:
∠B≅∠C
( since the angle opposite to equal side are equal )
- Also, we see that the line AD is perpendicular to side BC.
Hence, we have:
∠BDA≅∠CDA
( Since both the angles have equal measure )
- Hence, as two angles of a triangle are congruent to each other so the third angle will also be congruent.
( Since m∠B=m∠C
and m∠ADB=m∠ADC
⇒ m∠B+m∠ADB=m∠C+m∠ADC--------------(1)
By triangle sum theorem we have:
In ΔADB
m∠B+m∠ADB+m∠DAB=180°
⇒ m∠DAB=180°-(m∠B+m∠ADB)
and in ΔADC by triangle sum theorem we have:
m∠DAC=180°-(m∠C+m∠ADC)
Hence, by equation (1) we have:
m∠DAB=m∠CAD )
