# Circle - 8th grade (13y) - math problems

#### Number of problems found: 292

• Square and circle Into square is inscribed circle with diameter 10 cm.What is difference between circumference square and circle?
• Circumscription Calculate radius of the Circumscribed circle in the rectangle with sides 20 and 19. It can be rectangle inscribed by circle?
• Circle chord What is the length x of the chord circle of diameter 115 m, if the distance from the center circle is 11 m?
• Circle r,D Calculate the diameter and radius of the circle if it has length 26.59 cm.
• Circular flowerbed Circular flowerbed with diameter 8 m we split by concentric circle to circle and annulus with the same area. Find the radius of the circle.
• Circle - simple Calculate the area of a circle in dm2, if its circumference is 31.4 cm.
• Desribed circle to rectangle Rectangle with sides 6 cm and 4 cm was circumscribed circle. What part of the content of the circle determined by the circumscribed circle occupies a rectangle? Express in perctentages(%).
• Two annuluses The area of the annular circle formed by two circles with a common center is 100 cm2. The radius of the outer circle is equal to twice the radius of the inner circle. Determine the outside circle radius in centimeters.
• Chord MN Chord MN of circle has distance from the center circle S 120 cm. Angle MSN is 64°. Determine the radius of the circle.
• Circle and rectangle A rectangle with sides of 11.7 cm and 175 mm is described by circle. What is its length? Calculate the content area of the circle described by this circle.
• Hexagon in circle Calculate the radius of a circle whose length is 10 cm greater than the circumference of a regular hexagon inscribed in this circle.
• Squaring the Circle Calculating side of the square with the same area as the circle of radius 18.
• Circle's chords In the circle there are two chord length 30 and 34 cm. The shorter one is from the center twice than longer chord. Determine the radius of the circle.
• Concentric circles There is given a circle K with a radius r = 8 cm. How large must a radius have a smaller concentric circle that divides the circle K into two parts with the same area?
• Rectangle and circle The rectangle ABCD has side lengths a = 40 mm and b = 30 mm and is circumscribed by a circle k. Calculate approximately how many cm is circle long.
• Circle in rhombus In the rhombus is an inscribed circle. Contact points of touch divide the sides to parts of length 19 cm and 6 cm. Calculate the circle area.
• Circle chord Calculate the length of the chord of the circle with radius r = 10 cm, length of which is equal to the distance from the center of the circle.
• OK circle Calculate the radius (circumradius) of the circle described right triangle with hypotenuse long 33 and one cathetus long 17.
• Inscribed circle The circle inscribed in a triangle has a radius 3 cm. Express the area of the triangle using a, b, c.
• Perimeter of circle Calculate the circumference of described circle to the triangle with sides 9,12,15 cm.

Do you have an interesting mathematical word problem that you can't solve it? Submit a math problem, and we can try to solve it.

We will send a solution to your e-mail address. Solved examples are also published here. Please enter the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...