In a triangle D, E and F are midpoints of sides AB and AC respectively. If BC=5.6cm and angle B=72degree find DE and angle ADE​

Question

In a triangle D, E and F are midpoints of sides AB and AC respectively. If BC=5.6cm and angle B=72degree find DE and angle ADE​

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Iris 2 weeks 2021-09-07T05:45:45+00:00 1 Answer 0 views 0

Answers ( )

    0
    2021-09-07T05:47:14+00:00

    Answer:

    Given :

    D and E are the mid-points of AB and AC respectively.

    ∴ 2AD=AB and 2AE=AC ……. (1)

    Area of a triangle =

    2

    1

    × base × height

    ∴ Area of △ABC=

    2

    1

    ×AC×AB

    Since ADE form a triangle,

    ∴ Area of △ADE=

    2

    1

    ×AE×AD

    =

    2

    1

    ×

    2

    AC

    ×

    2

    AB

    =

    4

    1

    ×

    2

    1

    ×AC×AB

    =

    4

    1

    (Area of △ABC)

    Area of △ADE=

    4

    1

    (Area of △ABC)

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