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Most of these questions are asking for circle calculations. Recall that the perimeter of a circle--the distance all the way around--is given by the expression [MATH]2\pi r[/MATH], where [MATH]r[/MATH] is the radius of the circle. Also recall that the area of a circle--the amount of space inside--is given by the expression [MATH]\pi r^2[/MATH].
This is question 1:
This figure is built from three rectangles and what appears to be two not-to-scale half circles. It asks for the perimeter all the way around and the area of the green region. Take note that there is a mixture of measurements in meters and centimeters.
An entire circle's worth of perimeter is exposed, and the circle in question has a diameter of 2000cm (which corresponds to a radius of 10m). The curved portion of the perimeter is simply [MATH]2\pi(10)[/MATH] meters. Of the rectangular portions, there is a 40m length, a 25m length, a 10m length and four distinct 8m lengths. There is also one more length that is not labeled: its measure is 40m - 25m - 10m. The sum of all of these figures is the perimeter of the total shape.
For area, the rectangular regions are trivial: simply multiply their widths by their heights. There is a 40m by 20m region, a 25m by 8m region and a 10m by 8m region. Last we have the circle again, with its 10m radius: its area is [MATH]\pi(10)^2[/MATH]. The total area of the green shape, therefore, is the sum of all of these partial areas.
The remaining questions are very similar in that you will be calculating areas and volumes from compound shapes by picking them apart into their constituent pieces.
