<em>2400 is increased by 30%.</em>
so,
2400 + (30/100 * 2400)
2400 + (30 * 24)
2400 + 720
3120
<em>this number is decreased by 20%.</em>
so,
3120 - (20/100 * 3120)
3120 - (2 * 312)
3120 - 624
2496
therefore, the final number will be 2496.
Answer:
(C) 2√15
Step-by-step explanation:
Recognize that all the triangles are right triangles, so are similar to each other. In these similar triangles, the ratio of the short side to the long side is the same for all.
... CB/CA = CT/CB
... CB² = CA·CT = 10·6 = 60 . . . . . . . . . . multiply by CA·CB; substitute values
... CB = √60 = 2√15 . . . . . . . take the square root; simplify
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<em>Comment on this solution</em>
The altitude to the hypotenuse of a right triangle (CB in this case) divides the hypotenuse into lengths such that the altitude is their geometric mean. That is ...
... CB = √(AC·CT) . . . . as above
This is true for any right triangle — another fact of geometry to put in your list of geometry facts.
Answer:
x = - 4 y = - 4
Step-by-step explanation:
x+y= - 8
-9x-6y=60
First, solve for x in the first equation:
x+y = - 8 Subtract y from both sides
x + y - y = -8 - y y cancels on the left
x = - 8 - y
Now plug in what you found for x into the 2nd equation and solve for y.
- 9x - 6y = 60
-9(- 8 - y) - 6y = 60 Multiply out
72 + 9y - 6y = 60
72 + 3y = 60 Subtract 72 from both sides
72 - 72 + 3y = 60 - 72 72 cancels on the left
3y = - 12 Divie both sides by 3
3y/3 = -12/3 3 cancels on the left because 3/3 = 1
y = -4
Now plug your answer for y back into the first equation to get x.
x + y = -8
x + (-4) = - 8 Add 4 to each side
x - 4 + 4 = - 8 + 4 4 cancels on the left
x = -4
x = - 4 and y = - 4
First solve for the other angles.
You know one angle is 15º.
The one across from it is also 15º since it is a vertical angle to the known 15º angle.
Both of those together gets 30º.
The whole thing is 360º, so just subtract 30 from 360 and divide.
360 - 30 = 330
Do the same for the 15x angle.
The one under/across to it is a vertical angle so is also 15xº.
Now you are left with 30xº = 330.
Just divide now.
330 / 30 = 11
x = 11
15x = 165
Checking your work:
15x = 165
15x = 165
15
15
Those are the angles.
Add those numbers together and make sure it adds up to 360º.
165 + 165 + 15 + 15 = 360
So this is correct.