Perimeter and Area Test - 4

Given perimeter of a semicircle =144 cm ⇒   r(π+2)=144 ⇒   r×36/7=144 ⇒ r=28cm
Area of semicircle   =(1/2πr²⁾=12×22/7×28×28  =1232cm²

Let the radius of original circle be r. ∴   Area of the circle =πr² Now, radius becomes tripled i.e., 3r Thus, area of the new circle =π(3r)² =9πr²=9×(original area)

Let the radius of the two circles be r and R respectively.

Then their circumferences will be 2πr and 2πR

Hence 2πr : 2πR = 4:9 so that r:R = 4:9

Squaring r²:R² = 16:81

Ratio of their areas πr²:πR² = r²R² = 16:81

Length of wire =2π×42 =84πcm Let x be the side of the square. We have, 4x=84π⇒x=21π Area of the circle: Area of the square =π(42)²:(21π)² =4:π=4:(2/27)=14:11

Square Centimeters to Square Meters formula
m² =cm²/10000.
cm² = 10000 m²
So, 10000 cm² is required to make 1 m²

P= 2×(l+B)=100
35+B=100/2=50
B=50-35=15

Here we equate the areas, i.e., AB×DL=BC×DM ⇒ 18×DL=12×10 ⇒ DL=(12×10)/18=20/3