Q18 of 35 Page 3

In rectangle READ. Find ∠EAR, ∠ RAD and ∠ROD.

Given, ∠ROE = 60

According to given figure, ∠AOE = 120, ∠AOD = 60 and ∠ROD = 120.


⟹In triangle AOE, consider ∠EAR = ∠DEA = x


∠AOE + ∠EAR + ∠DEA = 180


x + x + 120 = 180


2x + 120 = 180


2x = 60


x = 30, i.e. ∠EAR = 30


⟹In triangle AOD, consider ∠RAD, = ∠EDA = y


∠RAD + ∠EAR + ∠AOD = 180


y + y + 60 = 180


2y = 120


y = 60, i.e.∠RAD = 60.

More from this chapter

All 35 →
16

ABC is a right-angled triangle and O is the mid-point of the side opposite to the right angle. Explain why O is equidistant from A,B and C. (The dotted lines are drawn additionally to help you).

 17

In the above figure both RISK and CLUE are parallelograms. Find the value of x.

 19

In Fig. 17.29, suppose it is known that DE = DF. Then, is ΔABC isosceles? Why or why not?

 20

Determine the number of sides of a polygon whose exterior and interior angles are in the ratio 1 : 5.