What is the radius of a circle with an area of 154 square centimeters?

  • Thread starter Thread starter Superman89
  • Start date Start date
  • Tags Tags
    Assistance
AI Thread Summary
To find the radius of a circle with an area of 154 square centimeters, the formula A = πr² is used. Substituting A = 154 into the equation leads to r² = 154/π. By approximating π as 22/7, the equation simplifies to r = sqrt(7 * 154 / 22). Ultimately, the radius is determined to be 7 centimeters.
Superman89
Messages
17
Reaction score
0
I need help with this word problem.

What is the radius of a circle whose area is 154 square centimeters?
I know I'm suppost to use the formula A={\pi}r^2.
What do I need to do next?
 
Mathematics news on Phys.org
You know that A (the area) is 154 (square centimetres) so its merely a case of substituting A=154 into the formula and solving for r (given that {\pi} is a known value).
 
154 = π r^2

r^2 = 154 / π

r = sqrt(154 / π)

r = sqrt(7 * 154 / 22) [as π = 22 / 7 (approximately)]

r = sqrt(7 * 7)

r = 7cm
 
Thread 'Video on imaginary numbers and some queries'

Thread 'Video on imaginary numbers and some queries'

Hi, I was watching the following video. I found some points confusing. Could you please help me to understand the gaps? Thanks, in advance! Question 1: Around 4:22, the video says the following. So for those mathematicians, negative numbers didn't exist. You could subtract, that is find the difference between two positive quantities, but you couldn't have a negative answer or negative coefficients. Mathematicians were so averse to negative numbers that there was no single quadratic...
View full post »

Thread 'What Exactly is Dirac’s Delta Function? - Insight'

Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
View full post »
Thread 'Unit Circle Double Angle Derivations'

Thread 'Unit Circle Double Angle Derivations'

Here I made a terrible mistake of assuming this to be an equilateral triangle and set 2sinx=1 => x=pi/6. Although this did derive the double angle formulas it also led into a terrible mess trying to find all the combinations of sides. I must have been tired and just assumed 6x=180 and 2sinx=1. By that time, I was so mindset that I nearly scolded a person for even saying 90-x. I wonder if this is a case of biased observation that seeks to dis credit me like Jesus of Nazareth since in reality...
View full post »

Similar threads

B Understanding why πr^2 works for different area calculations
Replies
7
Views
2K
MHB How Much Should the Radius Increase to Enlarge the Circle's Area by b Units?
Replies
4
Views
2K
MHB What is the formula for finding the area of a circle?
Replies
2
Views
2K
MHB Explaining the Area of a Circle: Understanding A(r) = πr^2
Replies
4
Views
4K
I Geometry problem of interest with a 3-4-5 triangle
2
Replies
59
Views
2K
MHB How can language proficiency affect understanding of math concepts?
Replies
6
Views
2K
MHB What is the total area of the infinite number of inscribed squares?
Replies
3
Views
2K
B Circle tangent to two lines and another circle
Replies
2
Views
3K
MHB Exercise about the concept of functions
Replies
4
Views
1K
Calculate Circle Radius/Diameter from Surface Area
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top