As shown in the figure, the middle angle ACB of triangle ABC is equal to 90 degrees, CA is equal to 15cm, CB is equal to 20cm, and the circle C with Ca as the radius intersects AB at d to find the length of AD

As shown in the figure, the middle angle ACB of triangle ABC is equal to 90 degrees, CA is equal to 15cm, CB is equal to 20cm, and the circle C with Ca as the radius intersects AB at d to find the length of AD


In RT Δ ABC, ∠ C = 90 ° and 〈 AB = √ (AC & # 178; + BC & # 178;) = 25,
If e is used as de ⊥ AC, then de ∥ BC,
∴ΔADE∽ΔABC,∴AE/DE=AC/BCD=3/4,
Let AE = 3x (x > 0), then de = 4x, CE = 15-3x,
In RT Δ CDE, CD & # 178; = CE & # 178; + de & # 178;,
225=(15-3X)²+16X²
25X²-90X=0
X = 18 / 5 or x = 0 (rounding off), AE = 3x = 54 / 5
∴AD/AB=AE/AC=(54/5)/15=18/25,
∴AD=18.
I hope I can help you



The side length of a right triangle is 15cm, 10cm, and the largest square is drawn. The area of the square is


It is easy to know that when the four vertices of a square fall on the three sides of a triangle, the square has the largest area
Let the side length of a square be x, then the two triangles above and below are similar
(15-x) / 15 = x / 10 gives x = 6
So the maximum square area is: 6 * 6 = 36cm ^ 2
I hope my answer is useful to you!



Draw the largest circle in a square with a side length of 10 cm, and calculate the area of the shadow part


10×10-3.14×10/2×10/2
=100-78.5
=21.5 square centimeters