In a 30cm by 25cm rectangle, a quadrant of a circle of radius 7cm has been cut away from each corner. What is the perimeter of the part left? 

98cm

Explanation:

Dimension of rectangle = 30cm by 25cm

Length(l) = 30cm

Width(w) = 25cm

Perimeter of a rectangle = 2(l + w)

Quadrant of circle cut away of each side of the rectangle :

Radius = 7 cm =

That is, the dimension of the triangle reduces by 2 * 7 = 14cm

New length = 30 - 14 = 16cm

New width = 25 - 14 = 11cm

The four corners =( 4 × 2πr ) / 4

2πr = 2 × 22/7 × 7 = 44cm

Perimeter = 2(16cm + 11cm)

= 2(27cm)

Perimeter = 54cm + 44 = 98cm

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this

hi,

what occurs during a solar eclipse?

there are small tides across earth.

the moon is between earth and the sun.

p.s. im not sure if the first answer is correct because during a solar ecliphse there are spring tides and i dont know if they are the same.