The cone-shaped lampshade has a diameter of 30 cm and a height of 10 cm. How many cm2 of material will we need when we 10% is waste?

Correct result:

S =  934.492 cm2

#### Solution:

$D=30 \ \text{cm} \ \\ v=10 \ \text{cm} \ \\ \ \\ r=D/2=30/2=15 \ \text{cm} \ \\ q=1 + \dfrac{ 10 }{ 100 }=\dfrac{ 11 }{ 10 }=1.1 \ \\ \ \\ s=\sqrt{ v^2 + r^2 }=\sqrt{ 10^2 + 15^2 } \doteq 5 \ \sqrt{ 13 } \ \text{cm} \doteq 18.0278 \ \text{cm} \ \\ \ \\ S_{1}=\pi \cdot \ r \cdot \ s=3.1416 \cdot \ 15 \cdot \ 18.0278 \doteq 849.538 \ \text{cm}^2 \ \\ S=q \cdot \ S_{1}=1.1 \cdot \ 849.538=934.492 \ \text{cm}^2$

Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!

Please write to us with your comment on the math problem or ask something. Thank you for helping each other - students, teachers, parents, and problem authors.

Tips to related online calculators
Pythagorean theorem is the base for the right triangle calculator.

#### You need to know the following knowledge to solve this word math problem:

We encourage you to watch this tutorial video on this math problem:

## Next similar math problems:

The double ladder shoulders should be 3 meters long. What height will the upper top of the ladder reach if the lower ends are 1.8 meters apart?
• The right triangle
The right triangle ABC has a leg a = 36 cm and an area S = 540 cm2. Calculate the length of the leg b and the median t2 to side b.
• Equilateral triangle
The equilateral triangle has a 23 cm long side. Calculate its content area.
• The Chemistry test
The Chemistry test contained 8 questions, each with 3 points. Peter scored 21 points. How many percent did Peter write a test?
• Percents
How many percents is 900 greater than the number 750?
• Highway repair
The highway repair was planned for 15 days. However, it was reduced by 30%. How many days did the repair of the highway last?
• Persons
Persons surveyed:100 with result: Volleyball=15% Baseball=9% Sepak Takraw=8% Pingpong=8% Basketball=60% Find the average how many like Basketball and Volleyball. Please show your solution.
• Art school
Every fifth pupil 9A goes to art school. How many percent of pupils in class 9A go to art school?
• Holidays - on pool
Children's tickets to the swimming pool stands x € for an adult is € 2 more expensive. There was m children in the swimming pool and adults three times less. How many euros make treasurer for pool entry?
The double ladder is 8.5m long. It is built so that its lower ends are 3.5 meters apart. How high does the upper end of the ladder reach?
• A truck
A truck departs from a distribution center. From there, it goes 20km west, 30km north and 10km west and reaches a shop. How can the truck reach back to the distribution center from the shop (what is the shortest path)?
• Walking
Of the 450 students at the school, 432 walks to school. What percentage is this?
• Median in right triangle
In the rectangular triangle ABC has known the length of the legs a = 15cm and b = 36cm. Calculate the length of the median to side c (to hypotenuse).
• Percentages
52 is what percent of 93?
• Reward
Janko and Peter divided the reward from the brigade so that Peter got 5/8 of the reward. What percentage of Janko's reward got?
• Center traverse
It is true that the middle traverse bisects the triangle?
• Profit gain
If 5% more is gained by selling an article for Rs. 350 than by selling it for Rs. 340, the cost of the article is: