As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree

As shown in the figure, the elevation angle of C is ∠ CAD = 30 ° from a, the elevation angle of C is ∠ CBD = 45 ° from B, and the angle of view is ∠ ACB when measuring a and B from C=______ Degree

Method 1: ∵ - CBD is the outer angle of △ ABC, ∵ - CBD = ∵ CAD + ∵ ACB, ∵ - ACB = ∵ CBD - ∵ ACB = 45 ° - 30 ° = 15 °. Method 2: from the definition of adjacent complementary angle, ∵ - CBD = 180 ° - 45 ° = 135 °. ∵ - CAD = 30 °, ∵ CBA = 135 °, ∵ - ACB = 180 ° - CAD - ∵ CBA = 180 ° - 30 ° - 135 ° = 180 ° - 165 ° = 15 °

How to draw circle when drawing axonometric drawing with CAD

An ellipse is used to represent a circle on an isometric plane
If you are drawing on an isometric plane, use an ellipse to represent a circle viewed from an oblique angle. The easiest way to draw an ellipse with the correct shape is to use the isometric circle option of the ellipse command. The isometric option is available only when the style option of snap mode is set to isometric (see dsettings)
Note that to represent concentric circles, draw an ellipse with the same center instead of offsetting the original ellipse. Offsetting can produce an elliptical spline, but it cannot represent the desired scaling distance

How can CAD draw the common tangent of two circles?

Command:
Line specifies the first point: Tan to the snap tangent
Specify next point or [u]: Tan to snap tangent point
Specify next point or: press enter
So you can make the common tangent of two circles

How to draw the common tangent of two circles in AutoCAD?

Set - only capture the tangent point, the rest do not want to line directly