What is the value of x?

1) 10
2) 20
3) 30
4) 40

1) 10

Basic facts:

we can tell a right angle if there is a small square drawn where the angle measuring should be done

Step-by-step explanation:

Main step

90-60=30

30=3x

divide by 3

10 =x

the value of x is 10

so option 1

10

Step-by-step explanation:

we can see there is a right angle

right angles are 90 degrees

90-60=30

30/3=10

72 is the answer to this problem

ab will be equal to