Answer:
Numbers of students at a primary school before= 240
Number of increased students =42
Again,
Increased number of students in percent(%)= 42/240×100%= 17.5%
Therefore 17.5% students are increased this year.
The radii of the frustrum bases is 12
Step-by-step explanation:
In the figure attached below, ABC represents the cone cross-section while the BCDE represents frustum cross-section
As given in the figure radius and height of the cone are 9 and 12 respectively
Similarly, the height of the frustum is 4
Hence the height of the complete cone= 4+12= 16 (height of frustum+ height of cone)
We can see that ΔABC is similar to ΔADE
Using the similarity theorem
AC/AE=BC/DE
Substituting the values
12/16=9/DE
∴ DE= 16*9/12= 12
Hence the radii of the frustum is 12
1 nanometer = 1 * 10^9 meters
so 1 nanometer = 1 * 10^7 centimeters
375 nanometers = 3,75 * 10^5 centimeters
Petra can make 8 costumes with 12 yards of fabric
<h3><u>Solution:</u></h3>
Given that Petra was given 12 yards of fabric to make costumes for the school play
Each costume requires 
yards
<em><u>To find: number of costume Petra can make</u></em>
The number of costume Petra can make is calculated by dividing the total fabric she has by fabric needed for one costume
Total fabric she has = 12 yards
Fabric needed for 1 costume = 
yards
Therefore,
Thus petra can make 8 costumes with 12 yards of fabric
