Question

M angle D=? What is the degree of the angle?

Answer 1

Answer:

80°

Step-by-step explanation:

In ACB and ECD

AC =~ CE [ Given ]

BC =~ CD [ Given ]

<ACD =~ <ECD [ Vertical angles ]

Hence, ∆ ACB =~ ECD by SAS congruency of triangles.

Then, <B = <D

In ∆ABC , sum of all three angles must be 180°

<A + <B + <C = 180°

plug the values

$30 + < d \: + 70 = 180$

Add the numbers

$100 + < d = 180$

Move constant to R.H.S and change it's sign

$< d = 180 - 110$

Subtract the numbers

$< d = 80$ °

Hope this helps..

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