In ∆ABC, AB = 5 cm, BC = 8 cm and CA = 7 cm. If D and E are respectively the mid-points of AB and BC, determine the length of DE.
Given: AB = 5 cm
BC = 8 cm
CA = 7 cm
The Midpoint Theorem states that the segment joining two sides of a triangle at the midpoints of those sides is parallel to the third side and is half the length of the third side.
By the midpoint theorem,
DE = �AC
⇒ DE = � × 7 cm
⇒ DE = 3.5 cm
Hence, the length of DE = 3.5 cm
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