ANSWER:
For the first picture, it is the first answer. This is because of the Exterior Angle Theorem.
For the second picture, use the Exterior Angle Theorem again, but this time, solve for x.
The m∡B = 39°
ASAP HELP PLZ
1 answer:
Answer:
Perimeter=42cm
Step-by-step explanation:
It is given that AC is the angle bisector of the trapezoid ABCD which divides the trapezoid into two similar triangles that are △ABC and △ACD.
Now, it is also given that AB=9cm and CD=12cm.
Since, it is a trapezoid, then AB will be parallel to CD, thus
∠BAC=∠DCA (Alternate angles)
Also, it is given that ∠DAC=∠BAC
⇒∠DAC=∠DCA
Also, ∠ACD=∠ACB( Angle bisector)
Therefore, If the angles are equal, then the corresponding sides will also be equal. Hence, △ABC and △ACD are isosceles triangle, therefore
AB=BC=9cm and CD=AD=12cm
Now, the perimeter of trapezoid is the sum of all the four sides of the trapezoid, therefore
Perimeter=AB+AD+CD+BC
Perimeter=9+9+12+12
Perimeter=42cm
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