In RT △ ABC, the sum of two right angle sides AB and AC is 8. Let BC = x, find the function of area s of RT △ ABC with respect to X and the value range of X

In RT △ ABC, the sum of two right angle sides AB and AC is 8. Let BC = x, find the function of area s of RT △ ABC with respect to X and the value range of X

Let AB = y, then AC = 8-y
According to Pythagorean theorem, (8-y) power = x power + y power
Namely: x + 16y-64 = 0 (2)
The area of triangle is XY / 2 = s
That is y = (2S) / X (1)
Substituting (1) into (2) gives s = (64x-x cube) / 32

If △ ABC ≌ Δ DEF is known, and the perimeter of △ ABC is 12cm and the area is 6cm & sup2;, then the perimeter of △ DEF is_____ Cm, the area is______ cm²

12, 6, congruent triangles have the same perimeter area, exactly the same

In the isosceles right angle △ ABC, the length of the middle line on the hypotenuse is 5cm, then the length of the hypotenuse is 5cm______ Cm, the area is______ cm2．

According to the fact that the central line on the hypotenuse of a right triangle is equal to half of the hypotenuse, the length of the hypotenuse is 10cm, ∵△ ABC is an isosceles right triangle, and the length of the high line on the hypotenuse is 5cm, the area is 12 × 10 × 5 = 25cm2

It is known that the circumference of a rectangle is 38cm, and the length is 5cm more than the width

The sum of length and width is: 38 △ 2 = 19 (CM)
The width of the rectangle is (19-5) △ 2 = 7 (CM)
The length of the rectangle is: 7 + 5 = 12 (CM)
Rectangular area: 12 × 7 = 84 (square centimeter)