Answer:

Step-by-step explanation:
we know that

when
-------> complementary angles
so


Because
-------> complementary angles
In this problem the product of

is equal to

therefore

25 is the answer..............
Answer:
177 $
Step-by-step explanation:
20 x8 = 160
3x3= 9
4x2=8
8+9+160= 177
Answer:
150 oz.
Step-by-step explanation:
There are already 150 ounces of alloy of nickel.
Of this 150 oz, 70% is pure i.e. nickel content = 150(0.7) = 105 oz
Now available is
Nickel Other metals
105 45
Let x oz of pure nickel is added.
Then new alloy will have 105+x oz nickel in total of 150+x oz.
Percentage pure = 
Simplify to get

Hence answer is 150 oz should be added.