Build a 1-meter-wide stone road around a pool with a diameter of 8 meters. How many square meters is the area of this stone road?

Build a 1-meter-wide stone road around a pool with a diameter of 8 meters. How many square meters is the area of this stone road?

The radius of inner circle is: 8 △ 2 = 4 (m); 3.14 × [(4 + 1) 2-42] = 3.14 × [25-16] = 3.14 × 9 = 28.26 (M2). Answer: the area of stone road is 28.26 m2

The radius of a round flower bed is 5 meters. There is a circular path 2 meters wide outside the flower bed. How many square meters is the area of this path?

R = 5, r = 5 + 2 = 7, large circle area = 153.86, small circle area = 78.5, annular area = large small = 75.36

There is a round flower bed in the street garden with a radius of 7.5 meters. There is a 1.5 meter wide path around the flower bed. How many square meters is the area of the path?

[(7.5+1.5)^2-7.5^2]*3.14=77.715

Build a 1 meter wide path around a 10 meter diameter circular flower bed. What is the area of the path?

π × 62 - π × 52 = 34.54 M2

Build a one - meter - wide circular road around a 12 - meter - radius flower bed

3.14（13x13-12x12）=78.5

On the periphery of a round flower bed with a radius of 10 meters, build a one meter wide path along the flower bed to calculate the area of the path

10+1=11
11x11x3.14-10x10x3.14

There is a circular path with a width of 1 meter outside the circular flower bed with a radius of 9 meters. How many square meters is the area of this path?

The area of a large circle reduces the area of a circle
10*10*3.14-9*9*3.14
＝100*3.14-81*3.14
＝19*3.14
= 59.66 square meters

There is a small path around the circular flower bed. The radius of the flower bed is 4 meters, and the width of the path is 1.5 meters

Floor area = (4 + 1.5) × (4 + 1.5) × 3.14-4 × 4 × 3.14 = 44.745 square meters

The gardener paved a 1.2-meter-wide circular path around the 8.2-meter-diameter flower bed. How many square meters is the area of this circular path?

The radius of flower bed: 8.2 △ 2 = 4.1 (m) the area of path: 3.14 × (4.1 + 1.2) 2-3.14 × 4.12 = 3.14 × 28.09-3.14 × 16.81 = 88.2026-52.7834 = 35.4192 (M2) a: the area of path is 35.4192 m2

There is a round flower bed with a diameter of 8 meters, and a 3-meter-wide path is built around it. What is the area of this path?

Because the width of the circular path is 3 meters, the diameter of the flower bed is 8 meters, so r = 8 △ 2 = 4 (meters); r = 4 + 3 = 7 (meters), the area of the ring is: π × 72 - π × 42, = 49 π - 16 π, = 33 π, = 33 × 3.14, = 103.62 (square meters), a: the area of the path is 103.62 square meters