Answer:
Base = 32 cm
Height = 25 cm
Step-by-step explanation:
Area of a triangle can be calculated as:
![Area = \frac{1}{2}\times Base \times Height](https://tex.z-dn.net/?f=Area%20%3D%20%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20Base%20%5Ctimes%20Height)
We are given that the base of triangle exceeds the height by 7 cm. This can be expressed in an equation form as:
Base = Height + 7
Lets use B to represent base and H to represent height
B = H + 7
The equation of area can be stated as:
![Area=\frac{1}{2}bh\\\\ Area=\frac{1}{2}(h+7)(h)\\\\ 400=\frac{1}{2}h(h+7)\\\\ 800=h^{2}+7h\\\\ h^{2}+7h-800=0](https://tex.z-dn.net/?f=Area%3D%5Cfrac%7B1%7D%7B2%7Dbh%5C%5C%5C%5C%20Area%3D%5Cfrac%7B1%7D%7B2%7D%28h%2B7%29%28h%29%5C%5C%5C%5C%20400%3D%5Cfrac%7B1%7D%7B2%7Dh%28h%2B7%29%5C%5C%5C%5C%20800%3Dh%5E%7B2%7D%2B7h%5C%5C%5C%5C%20h%5E%7B2%7D%2B7h-800%3D0)
This is a quadratic equation which can be solved using a quadratic equation as shown below:
![h=\frac{-7+-\sqrt{49-4(1)(-800)} }{2(1)} \\\\ h=\frac{-7+-57}{2}\\\\h=-32,25](https://tex.z-dn.net/?f=h%3D%5Cfrac%7B-7%2B-%5Csqrt%7B49-4%281%29%28-800%29%7D%20%7D%7B2%281%29%7D%20%5C%5C%5C%5C%20h%3D%5Cfrac%7B-7%2B-57%7D%7B2%7D%5C%5C%5C%5Ch%3D-32%2C25)
Since the height cannot be negative, we'll consider the positive value only i.e height is equal to 25 cm.
Therefore, the length of base will be 25 + 7 = 32 cm.
![\boxed { \text {Cosine Rule : } a^2 = b^2 + c^2 - 2bc \cos(A) }](https://tex.z-dn.net/?f=%20%5Cboxed%20%7B%20%5Ctext%20%7BCosine%20Rule%20%3A%20%7D%20a%5E2%20%3D%20b%5E2%20%2B%20c%5E2%20-%202bc%20%5Ccos%28A%29%20%7D%20)
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9² = 12² + 15² - 2 (12) (15) cos (B)
81 = 144 + 225 - 360 cos(B)
81 = 369 - 360 cos (B)
360 cos (B) = 369 - 81
360 cos (B) = 288
cos (B) = 0.8
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Answer: Cosine B = 0.8
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![\boxed { \text {Cosine Rule : } a^2 = b^2 + c^2 - 2bc \cos(A) }](https://tex.z-dn.net/?f=%20%5Cboxed%20%7B%20%5Ctext%20%7BCosine%20Rule%20%3A%20%7D%20a%5E2%20%3D%20b%5E2%20%2B%20c%5E2%20-%202bc%20%5Ccos%28A%29%20%7D%20)
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12² = 15² + 9² - 2 (15)(9) cos (A)
144 = 225 + 81 - 270 Cos A
144 = 306 - 270 Cos A
270 Cos A = 162
Cos A = 3/5 or 0.6
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Answer: Cosine Angle A = 3/5
Answer:
Total number of dimes=6
Total number of nickels=12
Step-by-step explanation:
The expression for the total value of money Jayden has is;
Nickels have a value of= $0.05
Dimes have a value of= $0.10
Total value=(value of nickels×number of nickels)+(value of dimes×number of dimes)
where;
Total value=$1.20
Value of a nickel=$0.05
number of nickels=y, but y=2 x
Value of a dime=0.10
number of dimes=x
replacing;
1.20=(0.05×2 x)+(0.1×x)
0.1 x+0.1 x=1.2
0.2 x=1.2
x=1.2/0.2
x=6
y=2 x=2×6=12
Total number of dimes=6
Total number of nickels=12
Answer:
3
Step-by-step explanation:
x = 1
y = 1
6+4-7 = 3