Câu 6:
4.8l of oil weigh 3.648kg. How many liters of oil are there if they weigh 4.864kg?
Answer: There are  liters
(Write your answer as a decimal in the simplest form)

Câu 7:
Inspecting products of a factory, we find that there are 97 qualified products out of every 100 products on average. What percent of the total products is qualified products?
Answer:  %

Câu 8:
A rectangular field has a width of 24.5m and its area equals the area of a square with the sides of 35m. Find the perimeter of that rectangular field.
Answer: m

Câu 9:
The area of a triangle ABC is , take the point M on BC such that BM=MC and the point N on AC such that AN=NC. Find the area of the triangle AMN.
Answer:  

Câu 10:
A store sold 902kg of rice which is 10.25% of the total amount of rice. How many kilograms of rice were there in that store at first?
Answer: There were  kilograms

1.  Two bisector BD and CE of the triangle ABC intersect at O. Suppose that BD.CE = 2BO.OC . Denote by H the point in BC such that .\(OH⊥BC\) . Prove that AB.AC = 2HB.HC

2. Given a trapezoid ABCD with the based edges BC=3cm , DA=6cm ( AD//BC ). Then the length of the line EF ( \(E\in AB,F\in CD\) and EF // AD ) through the intersection point M of AC and BD is ............... ?

3. Let ABC be an equilateral triangle and a point M inside the triangle such that \(MA^2=MB^2+MC^2\) . Draw an equilateral triangle ACD where \(D\ne B\) . Let the point N inside \(\Delta ACD\) such that AMN is an equilateral triangle. Determine \(\widehat{BMC}\) ?

4. Given an isosceles triangle ABC at A. Draw ray Cx being perpendicular to CA, BE perpendicular to Cx \(\left(E\in Cx\right)\) . Let M be the midpoint of BE, and D be the intersection point of AM and Cx. Prove that \(BD⊥BC\)