Question

EGiven ADEF, which is not equal to cos(F)?5O sin(F).O sin(D).O tan(F).O cos(D).DF52

Answer 1

Given the following sides of the triangle:

a = 5, b = 5, c = 5 √2

Let's find the cos of angle F:

`\cos ^(-1)(a^2+b^2-c^2)(2ab)/(\square)`
`\cos ^(-1)(5^2\text{ +( 5}√(2))^2\text{ - }5^2)(\square)/(\square)2\cdot\text{ 5 }\cdot\text{ 5}√(2)`
`F\text{ }\approx\text{ 45}\circ\text{ }\Rightarrow\text{ cos 45 = (}√((2))(2)/(\square)`

The correct option is D. Cos (D) because the sides a and b are equal and this is an isosceles triangle

In addition, angles D and F are equal (45 degrees)