Help me with geometry. I don’t understand this

Step-by-step explanation:

The objective is to find the missing angles.

It is given that <DOE = 53° and <AOF = 51°.

Then, the angle b can be calculated by the angel sum property of triangle as,

<AOF + <b + <DOE = 180⁰

51⁰ + b + 53⁰ = 180⁰

b + 104⁰ = 180⁰

b = 180⁰ - 104⁰

b = 76⁰

From figure, line BE and AD are intersecting lines. Then, by the property of vertically opposite angles,

<b = <d

<d = 76⁰

From figure, line BE and AD are intersecting lines. Then, by the property of vertically opposite angles,

<a = <AOF

<a = 51⁰