# Equilateral 7962

After a long dinner, inside a lounge in the shape of a square ABCD, a drunken shopper E lies in such a way that the triangle DEC is equilateral. Spy F lies on the edge of BC, with |EB|=|EF|. What is the size of the angle CEF?

### Correct answer:

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#### You need to know the following knowledge to solve this word math problem:

**algebra**- expression of a variable from the formula
**planimetrics**- right triangle
- triangle
- square
**basic functions**- reason
**goniometry and trigonometry**- tangent
- arctangent

#### Units of physical quantities:

#### Grade of the word problem:

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