Twenty-five lamps are placed around a circle-shaped garden. how many straight lines could be found if each lamp is connected to all the rest ?

300

Step-by-step explanation:

every lamp can connect other lamps ，from the first ，it can connect the other 24 lamps，and then， the second ，can also connect other 24 。but the line between the first and the second is counted twice。

so it would be：

（1+2+3+...+24）×24÷2=300

6.9

step-by-step explanation:

simple math really

6 1/2 times 0.6 = 3.9

but if you are just doing 6 and not 6 1/2 then the answer is 3.6

step-by-step explanation:

there is a formula i can give you:

it is r^2*n*sin(360/n) divided by 2 where r represents the "radius" and n is the number of sides.

plug them in:

(10sqrt(3))^2*6*sin(360/6) divided by 2

100*3*6*sin(60) divided by 2

900*sin(60)

900*sqrt(3)/2

450*sqrt(3)

approx is 779.4 cm^2