As shown in the figure, in △ ABC, ad ⊥ BC, CE ⊥ AB, perpendicular feet are D and e respectively, ab = 6, ad = 5, BC = 4 are known, and the length of CE is calculated

As shown in the figure, in △ ABC, ad ⊥ BC, CE ⊥ AB, perpendicular feet are D and e respectively, ab = 6, ad = 5, BC = 4 are known, and the length of CE is calculated

∵ ad ⊥ BC, CE ⊥ AB, ∵ s △ ABC = 12bc · ad = 12ab · CE, that is, 12 × 4 × 5 = 12 × 6 · CE, the solution is CE = 103

Known: as shown in the figure, points D, e and F are on BC, Ca and ab respectively, de ‖ Ba and DF ‖ ca. to verify: ∠ a = ∠ FDE, there is still a reason

Solution 1: ∵ de ∥ Ba, DF ∥ Ca, ∵ quadrilateral afde is parallelogram, (the definition of parallelogram), ∵ a = ∵ FDE (the parallelogram is diagonally equal)
Solution 2: ∵ de ∥ Ba, ∵ B = ∵ EDC, ∵ DF ∥ Ca, ∵ C = ∵ FDB, and the sum of ∵ ABC's three internal angles is 180 °, and ∵ FDB + ∵ FDE + ∵ EDC = 180 ° (horizontal angle definition) ∵ a = ∵ FDE (equivalent substitution)

Known: as shown in the figure, D, e and F are the points on BC, Ca and ab respectively, ed ‖ AB and DF ‖ AC. try to explain ∠ FDE = ∠ a solution: ∵ de ‖ AB (& nbsp; known & nbsp;) ∵ a=______ ∵ DF ∥ AC & nbsp; known & nbsp______ ∴∠A=∠FDE．

∵ de ‖ AB (& nbsp; known & nbsp;) ∵ a = ∠ CED (two lines are parallel, equal angle), ∵ DF ‖ AC (& nbsp; known & nbsp;) ∵ CED = ∠ FDE (two lines are parallel, equal angle), ∵ a = ∠ FDE

About the length change of longitude and latitude, shape characteristics, division starting point, direction indication, hemisphere division

Longitude: equal length
They are semicircles, intersecting at the poles, corresponding to two meridians to form a complete meridian circle
North South Pole
Indicates the north-south direction
The Western Hemisphere is 160 degrees east longitude to 20 degrees west longitude; the eastern hemisphere is 20 degrees west longitude to 160 degrees east longitude
Latitude: the length gradually shortens from the equator to the poles
Parallels are closed loops of weft
Indicates the east-west direction
With the equator as the boundary, the northern hemisphere is to the north and the southern hemisphere is to the south