Q3 of 14 Page 77

Tirtha draws two straight lines PQ and XY which intersect at O. Let’s measure the vertically opposite angles by protractor.

Let us consider the two lines to be drawn in following way:


Let ∠POX = ∠1 and ∠YOQ = ∠3 and ∠POY = ∠4 and ∠QOX = ∠2.


Now let us measure the angles one by one with help of protractor.


So ∠1 = 60°


∠2 = 120°


∠3 = 60°


∠4 = 120°


After measuring these angles, we can notice that the opposite angles are equal.


That is ∠1 = ∠3 = 60°


∠2 =∠4 = 120°


One more thing which can be noticed is that sum of all the angles is 360°.


That is ∠1 + ∠2 + ∠3 + ∠4 = 360°.


More from this chapter

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2

Let’s try to write the measurement of the angles from the figure given below:


∠1=35°
 ∠2=?
∠3=?
∠4=?


write.


 2

Let’s try to write the measurement of the angles from the figure given below:


∠TOS=20°
 ∠POQ=60°
 ∠POT=?
∠ROP=?
∠QOS=?


 4

Let’s try to find out the answer to the questions give below studying the figure beside.


i. Let’s write the names of two complementary angles.


ii. Let’s write the names of two supplementary angles.


iii. Let’s write the names of two vertically opposite angles.


 5

If two straight line intersect each other, then the measurement of vertically opposite angles are equal – prove it logically.