Applying the midsegment theorem and the definition of isosceles triangle:
DE = 4.5 units
m∠CAB = 45°
The image that shows ΔABC is attached below.
Since AB = BC, therefore, ΔABC is an isosceles triangle.
This implies that, the base angles will be equal.
Thus:
If m∠ABC = 90°, therefore,
m∠CAB = ½(180 - 90)
m∠CAB = 45°.
DE is the midsegment of the triangle, and is parallel to the third side, CA = 9 units.
Based on the midsegment theorem, we have the following equation:
DE = ½(9)
DE = 4.5 units.
Therefore, applying the midsegment theorem and the definition of isosceles triangle:
DE = 4.5 units
m∠CAB = 45°
Learn more about midsegment theorem on:
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