GeometryName: ______

#4 Finding Unknowns Dimensions & Shaded AreaPeriod: ____ 1/14/14

Write exact answers as well as decimal approximations rounded to the nearest hundredth.

  1. If the base of a triangle is 12 cm and the area is 42 cm, find the height.
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  1. If the base of a rectangle is 8 cm and the perimeter is 60 cm, find the height and then find the area.

  1. If the area of a circle is 81π cm2, find the circumference.
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  1. If the circumference of a circle is 15π inches, find the area.

  1. If the area of a circle is 32π cm2 , find the circumference.
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  1. If the circumference of a circle is 20 inches, find the area.

  1. A right triangle has area 90 cm2 and one leg 12 cm. Find the perimeter.
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  1. A right triangle has area cm2 and one leg 10 cm. Find the perimeter.

  1. What is the area of a circle whose circumference is  inches?
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  1. Given the circle and a rectangle (with base 24 cm and height 10 cm) below, find shaded area.

  1. If the circumference of the large circle is 24π cm, find the shaded area.
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  1. Given one larger semicircle with diameter 16 cm and two smaller semicircles, find the perimeter and the shaded area.

  1. Find the perimeter and the shaded area.
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  1. Find the shaded area.


  1. The cross has all 12 sides congruent and equal to 4. All angles are right angles. The diagonal line represents the diameter. Find the radius, then find the shaded area.

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  1. Semicircle with isosceles triangle. What is the exact perimeter of the figure?

  1. Three semicircles are drawn from the midpoints of the three sides of the triangle. Find the area of the triangle and the area of the shaded region.

  1. The circle below has an area of 25 and is divided into 8 congruent regions. What is the perimeter of one of these regions?
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  1. In the figure below, a small square is inside a larger square. What is the area, in terms of x, of the shaded region?

  1. In the figure below, the smaller circles each have a radius of 3. What is the perimeter of the shaded region?
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  1. The figure below consists of two circles that have the same center. If the shaded area is 64 square inches and the smaller circle has a radius of 6 inches, what is the radius, in inches, of the larger circle?

  1. In rectangle PQRS below, arcs QT and RT are quarter circles with centers at P and S, respectively. If the radius of each quarter circle is 1, what is the area of the shade region?
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  1. The circumference of the circle shown below is 2. What is the area of the shaded region?