Q(2) Solve all these questions – (86 × 2)

a) In fig. if ∠BOC = 7x + 20 and ∠COA = 3x, then find the value of x for which AOB becomes a 180°.

O

A

B

C

∠BOC = 7x + 20

∠COA = 3x

b) In fig. x : y : z = 5 : 4 : 6. If XOY is a straight line, find the value of x, y, z.

O

X

Y

Z

x

y

z

c) In a right angle triangle, if one angle is 30°, find the other two angles.

Q(4) Define parallelogram. Write two properties.