3 years ago

Bob the builder is making 480kg of concrete mix

1 answer:

5 0

To answer this item, we are first to determine the common factor between the amounts of the cement, sand, and gravel.

If we let x be this factor, the amount of the cement would be x. Similarly, the amount of sand is 3x, and lastly the amount of gravel is 4x. Then, we establish the equation that would let us relate the amounts.

x + 3x + 4x = 480

Simplifying,

8x = 480

x = 60

Hence, the amount of cement is 60 kg, that of sand is 180 kg. Lastly, the amount of gravel is 240 kg.

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The angle θ lies in Quadrant II. sinθ=3/4 What is cosθ ?

Elden [556K]

Hello from MrBillDoesMath

Answer:

[email protected] = - sqrt(7)/ 4

which is choice B

Discussion:

This problem can be solved by drawing triangles and looking at ratios of sides or by using the trig identity:

([email protected])^2 + (sin2)^2 = 1

If [email protected] = 3/4 , the

([email protected])^2 + (3/4)^2 = 1 => (subtract (3/4)^2 from both sides)

([email protected])^2 = 1 - (3/4)^2 = 1 - 9/16 = 7/16

So...... taking the square root of both sides gives

[email protected] = +\- sqrt(7)/ sqrt(16) = +\- sqrt(7)/4

But is [email protected] positive or negative? We are told that @ is in the second quadrant and cos(@) is negative in this quadrant, so our answer must be negative

[email protected] = - sqrt(7)/ 4

which is choice B

Thank you,

Mr. B

4 0

3 years ago

Answer==>x+2 process?

coldgirl [10]

Step-by-step explanation:

hope it helps . please give brainliest