The questions on the blackboard are: OM=?, ON=? for the first diagram. OM=?, ON=? for the second diagram. OB=? for the third diagram.

Analysis of the Blackboard Content:

The image displays a blackboard with three geometric diagrams and associated questions written in chalk. The diagrams appear to be related to circles, tangents, and angles, common in geometry or trigonometry lessons.

Diagram 1:

• A circle with center labeled '0'.
• A line segment labeled 'OM' appears to be a radius or a line to a point on the tangent.
• A point 'M' is marked on a line tangent to the circle.
• An angle of 30° is indicated.
• Questions: OM=?, ON=?

Diagram 2:

• A circle with center labeled '0'.
• Points 'M' and 'N' are marked on lines tangent to the circle.
• Segments labeled 'OM' and 'ON' likely represent distances or radii.
• Angles of 40° and 45° are indicated.
• Questions: OM=?, ON=?

Diagram 3:

• A circle with center labeled '0'.
• Points 'A', 'B', and 'C' are marked. 'B' appears to be an external point from which tangents 'BA' and 'BC' are drawn.
• An angle of 120° is shown, possibly related to the arc or the angle formed by tangents.
• A segment labeled '20' is shown, possibly a radius or a length.
• Question: OB=?

Additional Text:

• 'Дома:' (likely 'Homework:') is written at the top left.
• Labels '1', '2', and '3' are present next to each diagram, indicating separate problems.

Summary of Questions: The blackboard contains three geometry problems requiring the calculation of lengths (OM, ON, OB) based on the provided diagrams and angles.

Answer: The image contains geometry problems for homework, with specific questions related to calculating lengths based on given diagrams and angles. The exact numerical answers cannot be determined without further information or context regarding the geometric properties and values provided in each diagram.