Answer:
25
Step-by-step explanation:
The angle at C is 90 degrees, and BCD is a right triangle, so we can applythe Pythagorean theorem here -- 60²+m²=65², so 65²-60²=m²=625. The possible values for m are 25 and -25, and since m can't be negative, 25 is our answer as 25 is the square root of 625
The volume of the mineral = increase in volume of the water whuich is 16 - 8 = 8mls.
Therefore the mineral's density = 9.6 / 8
= 1.2 g/ ml answer
Let x = the other rational number.
x(66/7) = (48/5)
Solve for x to find your answer.
Answer:
216 boys
Step-by-step explanation:
450 students: 20% girls, 80% boys
450*20%=90 girls
450*80%=360 boys
Students having mobile phones: 40% (OF THE 90) girls, 60% (OF THE 360) boys
90*40%=36 girls
360*60%=216 boys
[We honestly don't need to care about the girls without mobile phones as they are only asking how many boys have mobile phones]
Properties of equality have nothing to do with it. The associative and commutative properties of multiplication are used (along with the distributive property and the fact of arithmetic: 9 = 10 - 1).
All of these problems make use of the strategy, "look at what you have before you start work."
1. = (4·5)·(-3) = 20·(-3) = -60 . . . . if you know factors of 60, you can do this any way you like. It is convenient to ignore the sign until the final result.
2. = (2.25·4)·23 = 9·23 = 23·10 -23 = 230 -23 = 207 . . . . multiplication by 4 can clear the fraction in 2 1/4, so we choose to do that first. Multiplication by 9 can be done with a subtraction that is often easier than using ×9 facts.
4. = (2·5)·12·(-1) = 10·12·(-1) = (-1)·120 = -120 . . . . multiplying by 10 is about the easiest, so it is convenient to identify the factors of 10 and use them first. Again, it is convenient to ignore the sign until the end.
5. = 0 . . . . when a factor is zero, the product is zero
