Find the Exact Value $\cos 85 ^ { \circ } \cos 40 ^ { \circ } + \sin 85 ^ { \circ } \sin 40 ^ { \circ }$

question 3

Multiple Choice

Find the exact value. $\cos 85 ^ { \circ } \cos 40 ^ { \circ } + \sin 85 ^ { \circ } \sin 40 ^ { \circ }$

• A) \(\frac { 3 \sqrt { 2 } } { 2 }\)
• B) \(\frac { \sqrt { 2 } } { 2 }\)
• C) \(1\)
• D) \(- \frac { \sqrt { 3 } } { 2 }\)
• E) none

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Definitions:

Arithmetically

Pertaining to arithmetic, the branch of mathematics dealing with the properties and manipulation of numbers.

Geometrically

In a manner that relates to geometry, the branch of mathematics concerned with the properties and relations of points, lines, surfaces, and solids.

Concentric Zone Model

A theory in urban sociology that suggests cities grow in a series of rings emanating from the downtown area.

Business District

A region within a city where the bulk of office buildings, commercial properties, and financial institutions are located.