Question

three angles of a quadrilateral are 100 degree, 90degree and 110degree what is the fourth angle
options are:
a) 30degree
b)120 degree
c)160degree
d)60 degree​

Answer 1

Answer :

›»› The forth angle of a quadrilateral is 60°.

Step-by-step explanation :

Given :

• Three angles of a quadrilateral are 100°, 90° and 110°.

To Find :

• Fourth angle of a quadilateral = ?

Solution :

Let us assume that, the fourth angle of a quadrilateral is "x".

As we know that

The sum of all four angles of a quadrilateral is 360°. This statement is known as 'angle sum property of quadilateral'.

→ 100 + 90 + 110 + x = 360

→ 190 + 110 + x = 360

→ 300 + x = 360

→ x = 360 - 300

→ x = 60

Hence, the fourth angle of a quadrilateral is 60°.

So, option (d) 60 degree is correct.

Verification :

The sum of all four angles of a quadrilateral is 360°.

→ 100 + 90 + 110 + 60 = 360

→ 190 + 110 + 60 = 360

→ 300 + 60 = 360

→ 360 = 360

Clearly, LHS = RHS.

Here both the conditions satisfy, so our answer is correct.

Hence Verified !

Answer 2

Answer:

Given :-

• Three angles of Quardilateral are 100,90, and 110

To Find :-

Fourth angle

Solution :-

Let the fourth angle be x

Now,

As we know that sum of all angles in a Quadrilateral is 360⁰.

$\sf \: 100 + 90 + 110 + x = 360$

$\sf \: 190 + 110 + x = 360$

$\sf \: 300 + x = 360$

$\sf \: x = 360 - 300$

$\sf \: x = 60$

Hence :-

The fourth angle of Quardilateral is 60⁰.

$\huge \bf \bigodot \: Option \: D$