# Expression of a variable from the formula - 7th grade (12y) - math problems

#### Number of problems found: 284

• Shape Plane shape has a maximum area 677 mm2. Calculate its perimeter if perimeter is the smallest possible.
• Cube wall The surface of the first cube wall is 64 m2. The second cube area is 40% of the surface of the first cube. Determine the length of the edge of the second cube (x).
• Triangles Equilateral triangle with side 40 cm has the same perimeter as an isosceles triangle with arm of 45 cm. Calculate the base x of an isosceles triangle.
• Cone and the ratio The rotational cone has a height 43 cm, and the ratio of the base surface to lateral surface is 5: 7. Calculate the surface of the base and the lateral surface.
• Rectangular trapezium Calculate the perimeter of a rectangular trapezium when its content area is 576 cm2 and sice a (base) is 30 cm, height 24 cm.
• Hotel The hotel has a p floors each floor has i rooms from which the third are single and the others are double. Represents the number of beds in hotel.
• Volume and area What is the volume of a cube which has an area of 361 cm2?
• Four circles 1) Calculate the circle radius if its area is 400 cm square 2) Calculate the radius of the circle whose circumference is 400 cm. 3) Calculate circle circumference if its area is 400 cm square 4) Calculate the circle's area if perimeter 400 cm.
• Simple equation 3 24 = n • 27, solve for n
• Guppies Audrey has some guppies in a fish tank. The ration of the oranges guppies to silver guppies is 3:5. She has 12y oranges guppies. Write the number of silver guppies she has in terms of y
• Twelve Twelve students work on a week forestry brigade. One hundred spruces will receive x CZK, one hundred pine y CZK. How many receive each one students did in one day if they planted a total of 25,000 spruces per week and 30,000 pine trees? Express by express
• Find unknown 2 Find unknown denominator: 2/3 -5/? = 1/4
• Area of a circle The circumference of the circle is 150.72 centimeters. Calculate the area of the circle.
• Floating of wood - Archimedes law What will be the volume of the floating part of a wooden (balsa) block with a density of 200 kg/m3 and a volume of 0.02 m3 that floats in alcohol? (alcohol density is 789 kg/m3)
• The wellbore The wellbore has a tributary of 2 m3 per hour. When there is no tapping, there are a stable 28 liters of water in the well. The pump suction basket is at the bottom of the well. At 14.00, the water was pumped out at a rate of 0.5 liters of water every se
• Perimeters A rectangle has a perimeter of 16p centimeters, it had a width of 2p centimeters. Each side of an equilateral triangle is 1/2 the length of the rectangle. Find the total perimeter of the rectangle and the triangle if p=8.
• Profitable company Three businessman decide to open up their own company. They agree to distribute the yearly profits made in the same ratio as their initial investments. They invest R 50 000, R 75 000 and R25 000, respectively. The profit made by the company in the first y
• The Earth The Earth's surface is 510,000,000 km2. Calculates the radius, equator length, and volume of the Earth, assuming the Earth has the shape of a sphere.
• A map A map with a scale of 1: 5,000 shows a rectangular field with an area of 18 ha. The length of the field is three times its width. The area of the field on the map is 72 cm square. What is the actual length and width of the field?
• What is bigger? Which ball has a larger volume: a football with a circumference of 66 cm or a volleyball with a diameter of 20 cm?

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Expression of a variable from the formula - math word problems. Examples for 7th grade (seventh).