In the $Δ A B C, ∠ B$ is a right angle, D and E are the mid-points of the sides AB=3 cm and AC= 5 cm respectively .Then, the length of DE is:

4 cm

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2 cm

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5 cm

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3 cm

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Solution

The correct option is B 2 cm

$A C^{2} = A B^{2} + B C^{2}$ [Pythagoras theorem]
$B C^{2} = (5)^{2} - (3)^{2}$
$B C^{2} = 25 - 9$
$B C^{2} = 16$
$B C = 4 c m$
Now,
DE= $\frac{1}{2}$ BC [Mid-point theorem]
DE= $\frac{1}{2} (4) = 2$ cm
Hence, the length of DE is 2 cm

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In the ΔABC,∠B is a right angle, D and E are the mid-points of the sides AB=3 cm and AC= 5 cm respectively .Then, the length of DE is:

The correct option is B 2 cm AC2=AB2+BC2 [Pythagoras theorem] BC2=(5)2−(3)2 BC2=25−9 BC2=16 BC=4cm Now, DE=12 BC [Mid-point theorem] DE= 12(4)=2 cm Hence, the length of DE is 2 cm

In the $Δ A B C, ∠ B$ is a right angle, D and E are the mid-points of the sides AB=3 cm and AC= 5 cm respectively .Then, the length of DE is:

The correct option is B 2 cm

$A C^{2} = A B^{2} + B C^{2}$ [Pythagoras theorem]
$B C^{2} = (5)^{2} - (3)^{2}$
$B C^{2} = 25 - 9$
$B C^{2} = 16$
$B C = 4 c m$
Now,
DE= $\frac{1}{2}$ BC [Mid-point theorem]
DE= $\frac{1}{2} (4) = 2$ cm
Hence, the length of DE is 2 cm