🎬 Lines and angles · Class 7 maths · 3:01
Lines and angles: Class 7 maths video
Master complementary, supplementary, adjacent, vertically opposite, and parallel line angles in this fun Class 7 maths lesson with Captain Calc.
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0:00 Class 7 maths. Lines and angles.
0:03 Welcome to HQ, cadet!
0:06 Captain Calc needs your help to solve line and angle mysteries today.
0:11 Complementary and Supplementary Angles.
0:15 Two angles are complementary if their sum is 90°.
0:20 Two angles are supplementary if their sum is 180°.
0:26 Try this one. Find the complement of 54°.
0:31 Complementary angles add up to 90°.
0:35 Subtract 54° from 90°.
0:39 90° - 54° = 36°.
0:44 So the answer is 36°.
0:47 Adjacent Angles and Linear Pairs.
0:50 Adjacent angles share a common vertex and a common arm, with no overlapping interior.
0:57 A linear pair consists of adjacent angles whose non-common arms form a straight line.
1:03 Try this one. Two angles form a linear pair. One angle is 65°. Find the other angle.
1:12 Linear pair angles add up to 180°.
1:17 Subtract 65° from 180°.
1:21 180° - 65° = 115°.
1:28 So the answer is 115°.
1:32 Vertically Opposite Angles.
1:34 When two straight lines intersect, they form four angles.
1:38 Angles opposite to each other at the intersection are called vertically opposite angles.
1:44 Try this one. Two lines intersect. One angle is 72°. Find the vertically opposite angle.
1:54 Vertically opposite angles are equal.
1:57 So the opposite angle is also 72°.
2:01 So the answer is 72°.
2:04 Parallel Lines and Transversal Angles.
2:08 A transversal is a line that intersects two or more lines at distinct points.
2:14 When a transversal cuts two parallel lines, corresponding angles are equal, and alternate interior angles are equal.
2:22 Try this one. Two parallel lines are cut by a transversal. One corresponding angle is 65°. Find the other corresponding angle.
2:33 Corresponding angles are equal when lines are parallel.
2:38 Therefore, the other angle is 65°.
2:42 So the answer is 65°.
2:45 Your turn. Find the complement of 48° (in degrees). Pause the video, and try it.
2:54 The answer is 42.
2:56 Well done! Now try the practice and the quiz in this lesson on LearnFun.
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