3 times a # (# isn't specified, so you should use a variable): 3x
result is 5: =5
Put it all together: 3x=5
Answer:
there are 27 female
Step-by-step explanation:
Answer: There are eight steps and two methods. I will be showing you one of them. If you're wondering, I am in 7th grade. I go to K12 online school.
Step-by-step Explanation: 1. Add together the lengths of the bases. The bases are the 2 sides of the trapezoid that are parallel with one another. If you aren’t given the values for the base lengths, then use a ruler to measure each one. Add the 2 lengths together so you have 1 value.[1]
For example, if you find that the top base (b1) is 8 cm and the bottom base (b2) is 13 cm, the total length of the bases is 21 (8 cm + 13 cm = 21 cm, which reflects the "b = b1 + b2" part of the equation).
2. Measure the height of the trapezoid. The height of the trapezoid is the distance between the parallel bases. Draw a line between the bases, and use a ruler or other measuring device to find the distance. Write the height down so you don’t forget it later in your calculation.[2]
The length of the angled sides, or the legs of the trapezoid, is not the same as the height. The leg length is only the same as the height of the leg is perpendicular to the bases.
3. Multiply the total base length and height together. Take the sum of the base lengths you found (b) and the height (h) and multiply them together. Write the product in the appropriate square units for your problem.[3]
In this example, 21 cm x 7 cm = 147 cm2 which reflects the "(b)h" part of the equation.
4. Multiply the product by ½ to find the area of the trapezoid. You can either multiply the product by ½ or divide the product by 2 to get the final area of the trapezoid since the result will be the same. Make sure you label your final answer in square units.[4]
For this example, 147 cm2 / 2 = 73.5 cm2, which is the area (A).
You can compute both the mean and second moment directly using the density function; in this case, it's
Then the mean (first moment) is
![E[X]=\displaystyle\int_{-\infty}^\infty x\,f_X(x)\,\mathrm dx=\frac1{80}\int_{670}^{750}x\,\mathrm dx=710](https://tex.z-dn.net/?f=E%5BX%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20x%5C%2Cf_X%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cfrac1%7B80%7D%5Cint_%7B670%7D%5E%7B750%7Dx%5C%2C%5Cmathrm%20dx%3D710)
and the second moment is
![E[X^2]=\displaystyle\int_{-\infty}^\infty x^2\,f_X(x)\,\mathrm dx=\frac1{80}\int_{670}^{750}x^2\,\mathrm dx=\frac{1,513,900}3](https://tex.z-dn.net/?f=E%5BX%5E2%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20x%5E2%5C%2Cf_X%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cfrac1%7B80%7D%5Cint_%7B670%7D%5E%7B750%7Dx%5E2%5C%2C%5Cmathrm%20dx%3D%5Cfrac%7B1%2C513%2C900%7D3)
The second moment is useful in finding the variance, which is given by
![V[X]=E[(X-E[X])^2]=E[X^2]-E[X]^2=\dfrac{1,513,900}3-710^2=\dfrac{1600}3](https://tex.z-dn.net/?f=V%5BX%5D%3DE%5B%28X-E%5BX%5D%29%5E2%5D%3DE%5BX%5E2%5D-E%5BX%5D%5E2%3D%5Cdfrac%7B1%2C513%2C900%7D3-710%5E2%3D%5Cdfrac%7B1600%7D3)
You get the standard deviation by taking the square root of the variance, and so
![\sqrt{V[X]}=\sqrt{\dfrac{1600}3}\approx23.09](https://tex.z-dn.net/?f=%5Csqrt%7BV%5BX%5D%7D%3D%5Csqrt%7B%5Cdfrac%7B1600%7D3%7D%5Capprox23.09)
