Question

If$ a + 10^o, 3a + 10^o, 5a - 10^o $\text{and}$ 3a - 10^o are the angles of a quadrilateral, then what is the value of $a$?

• A. 50^o
• B. 40^o
• C. 20^o
• D. 30^o

Answer 1

The correct option is

C

30^o

Given, a + 10^o, 3a + 10^o, 5a - 10^o , 3a - 10^o are the angles of a quadrilateral.

We know that the sum of angles of a quadrilateral is 360^o.

Therefore,

a + 10^o+3a + 10^o+ 5a - 10^o + 3a - 10^o = 360^o

$\Rightarrow$12a = 360^o

$\Rightarrow a=\frac{360}{12}$

$\Rightarrow a={30}^0$