Answer:

Step-by-step explanation:

Trigonometric functions which are related by having the same value at complementary angles are called cofunctions. Cofunctions of complementary angles are equal.
A. csc 20' = csc(90-70)=sec 70
B. cos 87' = cos (90-3)=sin 3'
C. csc 40' = csc(90-50) =sec50'
D. tan 15' = tan(90-75)= cot 75'
Among all the option c is not correct.
Option C is false.
1=7 3=21 5=35 7=49 13=91 hope this helps :)
Step-by-step explanation:

Answer:
You can determine the type of triangle using the following facts related to the converse of the pythag theorem
if a^2 + b^2 > c^2, then it is an obtuse triangle
if a^2+b^2<c^2, then it is an acute triangle
finally, if a^2+b^2=c^2, then it is a right triangle
<u><em>NOTE THAT C ALWAYS EQUALS THE LONGEST LENGTH OF THE TRIANGLE!!!</em></u>