Step-by-step explanation:
We can prove the statement is false by proof of contradiction:
We know that cos0° = 1 and cos90° = 0.
Let A = 0° and B = 90°.
Left-Hand Side:
cos(A + B) = cos(0° + 90°) = cos90° = 0.
Right-Hand Side:
cos(A) + cos(B) = cos(0°) + cos(90°)
= 1 + 0 = 1.
Since LHS =/= RHS, by proof of contradiction,
the statement is false.
Answer:
60 & 55
Step-by-step explanation:
1. the sum of the angles 1; 2 and 3 is 180°, then
m∠1=m∠2=m∠3; ⇒m∠3=60°;
2. m∠3=m∠r; ⇒ m∠r=60°;
3. m∠α= 180-(m∠r+65°)°; ⇒ m∠α=55°
all the details are in the picture.
Given:
The ratio of the measures of the sides of a triangle is 3:4:5.
Its perimeter is 48 inches.
To find:
The scale factor as a decimal, and the measure of each side of the triangle.
Solution:
Let x be the scale factor. Then the measures of sides of the triangle are 3x, 4x and 5x.
The perimeter of the triangle is 48 inches. It means the sum of all sides of the triangle is 48 inches.


Divide both sides by 12.


Now, the measures of sides are:


Similarly,


And,


Therefore, the scale factor is 4 and the measures of sides are 12, 16 and 20.