UrbanPro

Take Class 9 Tuition from the Best Tutors

  • Affordable fees
  • 1-1 or Group class
  • Flexible Timings
  • Verified Tutors

Search in

Find the area of a triangle two sides of which are 18cm and 10cm and the perimeter is 42cm.

Asked by Last Modified  

4 Answers

Learn Exercise 12.1

Follow 4
Answer

Please enter your answer

Given, Side a=18cm, Side b=10cm, Perimeter=42cm=a+b+c :. Putting value 42=18+10+c 42=28+c 42-28=c 14=c Now,S=(a+b+c)/2 :. Putting value S=42/2S=21 Now according to Heron's formula Area of a triangle=√{s(s-a)(s-b)(s-c)} :....
read more
Given,
Side a=18cm, Side b=10cm, Perimeter=42cm=a+b+c
:. Putting value 42=18+10+c
                       42=28+c
                       42-28=c
                       14=c
Now,S=(a+b+c)/2
:. Putting value S=42/2S=21
Now according to Heron's formula
Area of a triangle=√{s(s-a)(s-b)(s-c)}
:.    Putting value=√{21(21-18)(21-10)(21-14)}
                         =√{21(3)(11)(7)}
                         =√4851=21√11cm²
 
read less
Comments

Maths Teacher for classes 6th to 10th with 6 years experience and having my own YouTube Channel for clearing doubts

Perimeter of a triangle is the sum of all the three sides of that triangle. So, the third side of the triangle = 42cm - (18cm + 10cm) = 42cm - 28cm = 14cm. So, the three sides of the triangle are 18cm, 10cm and 14cm. Area of the triangle, using Heron's Formula is 69.65cm².
Comments

Let the third side be c. ∴ 18cm + 10cm + c = 42cm ∴ c = 42cm - 28cm = 14cm. ∴ the area of the triangle = √21 ( 21 - 10 ) ( 21 - 14 ) ( 21 - 18 ) = √21 × 11 × 7 × 3 = 21√11cm².
Comments

Given,Side a=18cmSide b=10cmPerimeter=42cm=a+b+c:. Putting value42=18+10+c42=28+c42-28=c14=cNow,S=(a+b+c)/2:. Putting valueS=42/2S=21Now according to Heron's formula-Area of a triangle=√{s(s-a)(s-b)(s-c)}:. Putting value=√{21(21-18)(21-10)(21-14)}=√{21(3)(11)(7)}=√4851=21&radi...
read more

Given,
Side a=18cm
Side b=10cm
Perimeter=42cm=a+b+c
:. Putting value
42=18+10+c
42=28+c
42-28=c
14=c
Now,
S=(a+b+c)/2
:. Putting value
S=42/2
S=21
Now according to Heron's formula-
Area of a triangle
=√{s(s-a)(s-b)(s-c)}
:. Putting value
=√{21(21-18)(21-10)(21-14)}
=√{21(3)(11)(7)}
=√4851
=21√11cm²

read less
Comments

View 2 more Answers

Related Questions

An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle.

Length of the equal sides = 12cm Perimeter of the triangle = 30cm Length of the third side = 30 - (12+12) cm = 6cm Semi perimeter of the triangle(s) = 30/2 cm = 15cm Using heron's formula, Area of the...
Damanpreet
0 0
9
Sides of a triangle are in the ratio of 12 : 17 : 25 and its perimeter is 540cm. Find its area.
Ratio of the sides of the triangle = 12 : 17 : 25 Let the common ratio be x then sides are 12x, 17x and 25x Perimeter of the triangle = 540cm 12x + 17x + 25x = 540 cm ⇒ 54x = 540cm ⇒ x = 10 Sides...
Swathi

A traffic signal board, indicating ‘SCHOOL AHEAD’, is an equilateral triangle with side ‘a’. Find the area of the signal board, using Heron’s formula. If its perimeter is 180 cm, what will be the area of the signal board?

The perimeter of a triangle is equal to the sumof its three sides it is denoted by 2S.2s=(a+b+c)s=(a+b+c)/2Here ,s is called semi perimeter of a triangle. The formula given by Heron about the area of atriangle...
Rajmohan
0 0
5

Now ask question in any of the 1000+ Categories, and get Answers from Tutors and Trainers on UrbanPro.com

Ask a Question

Recommended Articles

With the mushrooming of international and private schools, it may seem that the education system of India is healthy. In reality, only 29% of children are sent to the private schools, while the remaining head for government or state funded education. So, to check the reality of Indian education system it is better to look...

Read full article >

While schools provide formal education to the children, the home is where they start learning about things informally. Parents think that schools will take the initiative to educate their children. Well, this is partially true, as parents also play an essential role in bringing up their child. For the development of particular...

Read full article >

Appearing for exams could be stressful for students. Even though they might have prepared well, they could suffer from anxiety, tension etc. These are not good for their health and mind. However, following a few exam preparation tips can save them from all these and help them to score good marks. Let’s find out all...

Read full article >

Quality education does not only help children to get a successful career and life, but it also hugely contributes to society. The formal education of every child starts from school. Although there are numerous schools, parents find it challenging to choose the right one that would fit their child. It is difficult for them...

Read full article >

Looking for Class 9 Tuition ?

Learn from the Best Tutors on UrbanPro

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you
X

Looking for Class 9 Tuition Classes?

The best tutors for Class 9 Tuition Classes are on UrbanPro

  • Select the best Tutor
  • Book & Attend a Free Demo
  • Pay and start Learning

Take Class 9 Tuition with the Best Tutors

The best Tutors for Class 9 Tuition Classes are on UrbanPro

This website uses cookies

We use cookies to improve user experience. Choose what cookies you allow us to use. You can read more about our Cookie Policy in our Privacy Policy

Accept All
Decline All

UrbanPro.com is India's largest network of most trusted tutors and institutes. Over 55 lakh students rely on UrbanPro.com, to fulfill their learning requirements across 1,000+ categories. Using UrbanPro.com, parents, and students can compare multiple Tutors and Institutes and choose the one that best suits their requirements. More than 7.5 lakh verified Tutors and Institutes are helping millions of students every day and growing their tutoring business on UrbanPro.com. Whether you are looking for a tutor to learn mathematics, a German language trainer to brush up your German language skills or an institute to upgrade your IT skills, we have got the best selection of Tutors and Training Institutes for you. Read more