Three angles of a quadrilateral are 75º, 90º and 75º. The fourth angle is
a. 90º
b. 95º
c. 105º
d. 120º
Solution:
It is given that
Three angles of a quadrilateral are 75º, 90º and 75º
Consider x as the fourth angle
Using the quadrilateral angle sum property
Sum of all four interior angles is equal to 360º
We can write it as
75° + 90° + 75° + x = 360°
By further calculation
240° + x = 360°
x = 360° – 240°
So we get
x = 120°
Therefore, the fourth angle is 120º.
✦ Try This: Three angles of a quadrilateral are 55º, 90º and 65º. The fourth angle is a. 90º, b. 95º, c. 105º, d. 120º
☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 8
NCERT Exemplar Class 9 Maths Exercise 8.1 Problem 1
Three angles of a quadrilateral are 75º, 90º and 75º. The fourth angle is, a. 90º, b. 95º, c. 105º, d. 120º
Summary:
A quadrilateral is a polygon with four sides, four angles and four vertices. Three angles of a quadrilateral are 75º, 90º and 75º. The fourth angle is 120º
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